Catching the tide

Harry Potter - J. K. Rowling
F/M
G
Catching the tide
Summary
Ondine is startled when Severus Snape asks her to meet him to talk about her future... and to dress for warm weather.Or, Snape goes to the beach in hopes of catching the siren-witch that captured his heart.
Note
This is just a light, feel good fic I wanted to post in honour of all Snape lovers.
All Chapters Forward

Chapter 1

The future

Ondine had expected many things when Professor Snape asked her to meet. A final critique on her last potion, perhaps. A warning to tread carefully as she stepped into adulthood. Even a reluctant compliment, begrudgingly given for her academic excellence.

What she had not expected was:

"We should meet to discuss your future."

The words were delivered in his usual, clipped tone, free from fioritures. A declaration, not a request. And even though he wasn't her head of house, Ondine dared not refuse him. Her stomach twisted at the implication, heart hammering against her ribs as if trying to escape.

"Alright," she had managed, her voice more breathless than she intended.

"Tomorrow at two o'clock", he nodded.

"In your office, sir?"

"No," he said immediately. "These are delicate matters to discuss. The Three Broomsticks. Dress for warm weather."

Her head spun. Snape, outside Hogwarts, willingly? What was happening?

"Hum, alright?" she ventured, voice rising slightly at the end, unable to disguise her surprise. Snape being Snape ignored her silent plea and ploughed on. "Is there a significant other you might want us to join?", he added, his dark gaze unreadable.

A wave of heat slammed into her.  A significant other? Did he… was he… why would he ask that? Had he caught on her feelings ? Ondine's throat went dry, and to her utter horror, she stammered, "I… no …. I mean, I don't … there's". She sighed. "No, sir!"

His eyes didn’t waver from hers, deep pools of obsidian that seemed to study her reaction with meticulous interest. Was there a flicker of something—satisfaction? Relief? She couldn’t tell, and it unnerved her. The smirk she expected never came. He simply nodded, his face as impassive as ever. "Very well. Until tomorrow."

He strode away, utterly unaffected, while Ondine remained rooted to the spot, cheeks ablaze and mind racing. What in Merlin’s name was this meeting about?

The next day, she arrived at The Three Broomsticks in a light cotton dress and sandals, still half-convinced this was some kind of elaborate test. Or a dream. A cruel, beautiful dream she would wake up from at any moment. But when he walked in, her breath left her entirely.

Snape stood there, awaiting. Gone were the heavy, concealing robes. Instead, he wore a linen shirt, the sleeves rolled up to his forearms, revealing pale skin that had never seen much sun. The fabric moved like a veil, an startling contrast to his usual severe presence and billowing robes.

Ondine swallowed hard, feeling her pulse spike. Had he always been this... this? The sight of him in something so casual was mind numbing, intimate in a way she hadn’t expected. Ondine smiled despite her shock, feeling like she was being granted something miraculous; a part of him that no one else ever saw.

Snape approached with his usual presence, and she forced herself to remember how to breathe. He was watching her. Intently. Too intently. It wasn’t the usual detached scrutiny of a professor assessing a student’s potion work.

“Erm,” she began, voice betraying her nerves. “Why here?”

Snape didn’t smirk or sneer. He simply inclined his head slightly, dark eyes watching her with that same unreadable expression. “Fresh air.”

Ondine's forehead creased in wonder; her heart told her something was afoot beneath the surface of his usual poise. But she bit her tongue, unwilling to probe too soon.

“Now that you have graduated,” he added, “I can unravel my most hidden secret.”

Her breath caught. A secret? Her mind immediately spun into overdrive. A revelation about the war ? His past ? His feelings ?

“Sweet tooth. Let's get ice cream.”

Ondine blinked, mind screeching to a halt. Had she fallen into an alternate reality?

A strangled noise escaped her throat before she could stop it. “I… what?”

His lips twitched, ever so slightly, but his eyes remained solemn. He merely gestured towards the chimney, utterly composed, as though he hadn’t just shattered her entire sense of reality. Still reeling, she followed.

Ondine

She had always been such a curious child.

In his fifth year of teaching, Severus Snape still wore the mantle of grief and guilt like a second skin. It clung to him with every footstep through the cold stone halls of Hogwarts, whispering reminders of everything he’d lost, and everything he had yet to atone for.

And then came Ondine.

A first-year from Hufflepuff of all places—sunshine incarnate. Wide, storm-washed eyes that mirrored the sea on a stormless morning, and hair that flowed like wheat fields in August. She looked like she had never known sorrow.

Snape had expected to crush her spirit with a word, a glare, as he had done so many times before. Children were foolish. Fragile. Especially the happy ones. And yet… she worked. Tirelessly. As if he had opened a new world to her, and she was determined to master every inch of it. She soaked in his lessons with an intensity that unnerved him, absorbing his knowledge as though it were sacred text. Like a siren hoarding secrets instead of gold.

She was unlike anyone he'd taught.

Playful in nature—no doubt from her ancestry, half-siren, half-witch—yet her gaze always held something deeper, older. A liquid grace cloaked her movements, as though she was never quite bound to the ground. And while her fellow students whispered and gossiped and mocked her bloodline, she never flinched. She let their barbs slide over her as if she bore invisible scales, gliding through the tide of their ignorance toward deeper, calmer waters.

He’d watched it all in silence.

And year by year, she grew. Not just in height or magical prowess, but in presence. The child ripened into a young woman of startling poise, and more startling understanding. Her ability to brew potions with intuitive precision was unmatched in her year. She didn’t just follow instructions—she felt her way through the process, coaxing reactions with care and reverence. Water, after all, was her element, and in potion-making, it obeyed her with quiet loyalty.

It was in her third year that she started volunteering for extra sessions—detention, she claimed, though there had been no offense. He saw through the excuse, but he never questioned it. She sat at the far bench, reverently observing as he prepared rare drafts or dissected the mistakes of others. And when she asked questions, they were not the idle curiosities of a bored student—they were precise, sometimes startlingly perceptive.

Later, he would realize how it started.

She had knocked over a jar of doxy wings. Deliberately. He hadn't noticed at the time. The breaking glass, the resulting chaos, her sheepish look—all had seemed plausible enough. A misstep. An accident.

But years later, he’d recall the subtle glance she'd given him before her hand reached toward the jar. The tiny twitch at the corner of her lips when he assigned her detention. She'd wanted to be there.

It had irritated him at first. Who chose detention? Who grinned slightly when he handed down punishment?

And yet, she came. Dutifully. Even eagerly. Sometimes she barely spoke—just hovered nearby, watching him brew, eyes alert and glimmering with something he couldn't name. Not admiration, not quite. Something older. Something more dangerous.

He never mentioned the doxy wings again. He let her have her little ruse. And in time, those quiet sessions in the dungeon became... bearable. Then welcome. Then missed, when they were gone.

At first, he kept his distance. He answered curtly, corrected her with his usual biting tone. But it didn’t deter her. She simply nodded and tried again. Over time, their conversations drifted beyond potion theory. She spoke of the sea and its strange, silent wars—of deep, dark places where monstrous things lurked, and where her people still danced. She described moonlit rituals and ancient magic that hummed beneath the waves. In turn, he told her stories too—of rare elixirs, of forgotten branches of alchemy, of spells brewed from blood and grief.

He surprised himself with how much he told her.

By her fifth year, she had stopped being a child in his eyes. She had grown into herself, equal parts water and will. There was a quiet strength in her now, something bone-deep. She never raised her voice. She didn’t need to. She simply existed, calm and powerful, like the sea before a storm.

She never flinched when the Dark Lord was mentioned.

By her sixth year, she was among the top of her class. And even though he would never say it aloud, she was better than most of her peers. Far better. He had students who chased ambition, students who sought glory. Ondine sought mastery. And not for power, but for understanding.

There was something maddening about her calm. The way she never reacted with foolish impulse. The way she could look at him—really look—and never shy away. And somewhere between their quiet talks, he realized he was no longer simply guiding her to greatness.

He was falling.

Falling for the girl with sea-glass eyes who made the dungeons feel less cold, even though she was ten years his junior.

Give it time.

By seventh year, she had become a force to be reckoned with, challenging him in theory and discussion. He found himself leaning into her insights, considering things he never would have. Her voice had deepened slightly, her confidence sharpening. But still, she retained that ineffable softness—compassion that never dulled her intellect. She was kind without being blind, loyal without being naive.

He’d always feared attachment; he'd been burnt before, and knew the cost to be high. But Ondine was not a flame, she was water. She would drown his demons, quiet his mind.

And that terrified him more than anything else.

Because in her presence, he found something he had long since believed lost: peace.

She was his student. And he, her professor. He told himself he would wait. That nothing would ever happen unless she reached out first. But inside, Severus Snape—a man long resigned to cold nights and darker destinies—felt the ache of wanting.

He didn’t want to let her go.

He had never expected to care again. Not after Lily. Not after everything he had done in the name of love and vengeance.

But then came Ondine. And without even trying, she had become his beacon in the dark. His reminder that life still had meaning beyond war and regret. That perhaps—just perhaps—he was still capable of being loved.

Even though it was selfish to tether her in his dark world, he found he wanted to be selfish: he didn't want to let her go.

He wanted to stay in the warmth of her presence a little longer.

In the seven years she'd blessed his life, Ondine had become his beacon in the night.

 

Trebarwith sands

They flooed directly from The Three Broomsticks, then he apparated them in a flash. Disoriented, Ondine blinked at him before a gentle breeze murmured in her ear something familiar. Her eyes reluctantly left those of professor Snape to assess her surroundings; the sight that greeted her stole her breath entirely.

Trebarwith Strand.

The golden cliffs stretched along the coastline, jagged yet breathtakingly beautiful, softened by the endless expanse of blue that met the horizon. The waves danced as they crashed upon the rocky shore, retreating into the sea’s embrace before coming back, persistent, ceaseless. The air was thick with salt and warmth, the sun hanging lazily in the sky, casting shifting patterns over the water.

This was home.

Ondine’s heart clenched, overwhelmed by the sudden familiarity. Had chosen this place on purpose ? The realization sent a shiver through her entire being as they walked down the beach silently. She turned toward Snape; his gaze was fixed on the sea as the wind teased at his linen shirt, making him stand out. Tall, dark and brooding, framed by nature’s wild beauty.

The tide was low, the waves gentle. She slipped off her sandals and stepped into the cool water, feeling it ripple around her ankles, welcoming her. The sea was where she belonged. It whispered to her in recognition. A delighted laugh escaped her before she could stop it.

When she turned back, Snape was watching her like a looming tower guarding the shore. A hat had materialised on his head, giving him a strange domestic air.

He seemed to be studying her. His dark eyes burned into hers with quiet intensity, as though she were a puzzle he was desperate to solve but hesitant to unravel. Her heart pounded. Was he aware of how much she felt for him? Did he know how deeply she had fallen, how her dreams often drifted to his sharp features, his low, silken voice?

Then, to her utter astonishment, he too discarded his shoes and joined her.

Snape is treading in the water, with me, on a sunny day. Uh.

“So,” he began, voice as smooth as ever. “Have you considered your career path ?”

It was intimidating to speak of the future with the man she envisioned as her future. But Ondine had long shackled her dream. For the sake of realism, her heart was guarded; she would take the little she could get, and plunge into her second passion in life. Water, and its magic. Perhaps then, she might still be able to nurture a link with her former professor, if only through discussions and letters; Snape always seemed animated by the craft.

Would he respond to her letters, if she dared writing some ? When they debated about potions, his eyes alighted with passion and cunning. Just like her heart. His gaze had not left hers, causing her blood to race. Ondine inhaled sharply. “I wish to apprentice in potions.”

His expression sharpened, coiled with satisfaction. “You would be a fine apprentice. What do you think of Hogwarts ?"

The world tilted again.

“You…”, she swallowed, heartbeat deafening. “You would offer?”

“Aye.” He nodded, as if confirming something to himself. “I am grumpy and demanding, and you know my patience isn't great with fools. But if you demonstrate your usual wittiness, you have nothing to fear.”

A breathless laugh left her before she could stop it. “It would be..."

Fantastic, wonderful, amazing… and it would crush me to be by your side everyday, never to have you.

"… an honour, sir.”

Her hands clenched slightly, fingers tingling with the urge to reach for him. But then he spoke again, and the warmth in her chest turned to ice.

“The Potter brat will be in next year. You are no fool, you know the Dark Lord may resurface.”

The Dark Lord.

Ondine's breath caught at the mere mention of Voldemort. If he emerged again, war would be inevitable, consuming the wizardry world again. She could see it in his face—the exhaustion, the unrelenting duty that would keep him shackled. She knew he'd been to war already. The mere mention of Potter darkened his eyes, a reminder of heavy promises he had mentioned, but never explained.

She had no doubt the cold, aloof professor would fight with everything he had.

And what of her? Was she ready for this? Could she truly stand beside him, knowing what was to come? Ondine had been too young to understand the war, last time. Merely a child when the Potter couple died, leaving the wizardly world in revelry and chaos.

The young woman clenched her fists; there was no backing away from this. If she walked away now, she would regret it for the rest of her life.

“Why are you telling me this?” she whispered.

The sea lapped at their feet, gentle and persistent. For a long moment, he said nothing. Then, in a voice quieter than the waves, he replied: “Because you deserve to know what you are walking into.”

Her breath hitched. He wasn’t pushing her away. He was letting her choose.

And in that moment, as the tide rolled in, she knew she already had.

Regrets

“I have many regrets in my life, and did not wish to add more. So I will ask, and I want you to be assured you are allowed to refuse.”

Ondine felt her brows furrows at the seriousness of his declaration; Professor Snape never was one to joke around, except with the few that understood his very dry wit. That she was one of those he directed said wit to was a privilege.

 But that declaration felt like a solemn vow, and despite the water dancing around her ankles merrily, she felt the air grow still between them.

“This is not a teacher’s request", he stated ominously. "Do you understand ?”. His dark eyes smouldered beneath the rim of his hat, awaiting a confirmation.

“I do”, she responded, her heartrate peaking beneath the linen blouse.

What could warrant such ceremony, if not a dire demand ? Would he ask her to join the Order of the Phoenix should Voldemort return ? Or to keep an eye on Harry Potter, maybe, when he couldn’t ? The thrill of becoming a right winged man – er, woman - sent blood rushing in her veins. And the sea responded to her emotions; she felt it coming, strong and playful, a warning of the incoming tide. Her head whipped aside, her entire being attuned to the energy that came their way.

“We should back away”, she urged, already in movement.

The professor did not argue, trusting her implicitly as she retreated a good thirty feet away from the shore; they could not perform elemental magic in front of so many muggles. The wave still caught them, swirling water crashing around their calves and spraying upon the hem of her dress. Ondine squeaked in both fright and delight, watching the long procession of seafoam and wavelets expand behind them, reaching far over the former shoreline as it spread.

When her eyes returned to professor Snape, she found the bottom of his pants completely soaked. But he seemed completely unfazed by the impromptu shower, feet firmly planted in the sand.

“Oh my !”, she exclaimed. “The sea caught you.”

“It definitely did”, he crooned, as if partaking in a secret she had yet to uncover.

“I’m sorry”, she giggled slightly. “I should have reacted sooner.”

A dark eyebrow lifted beneath his mane of jet-black silk.

“The water is of unforeseeable nature, as you well know.”

She remembered a discussion, mere months ago, in potion class about the unique disposition of water. About how, if the brewer wasn’t up to the task, the medium itself would not respond well and refuse to link ingredients that could have matched. Contrary to popular beliefs, potions were no mere cooking recipes. Brewing meant giving it a heart, a shape, a consistence. To transform ingredients to create a whole different existence. More than skill and precision, it required care, love, and most of all, belief.

As water retreated, dragging sand beneath their toes, Ondine couldn’t help but wonder what she was missing. And, judging by the spark of uncertainty that seemed to dance behind those impenetrable walls of occlumency, she felt anticipation build in her chest until she was ready to burst. But as gifted as she was in potion class, Ondine never was one to shield her emotions; Professor Snape had an unfair advantage over her. Yet, rather than callously remark upon it, he chose to open the walls of his mind.

Gradually, she watched his features relax under the rim of his hat, creating an incredible sense of vulnerability. She had never seen him so open, and the image would remain etched in her mind for years to come.

“Ondine”, he started, using her first name for the first time. The sonority rolled on his tongue like pebbles under a tidal wave, his French accent spotless. Her breath caught, and her aura reached for his in curiosity.

“I wished to ask… to offer…”

He paused then, eyes roaming the expense of the ocean for a moment, as if searching for the right words. So unlike his usual self, callous and self-assured, never taken aback as his prose lashed out at clumsy students. What could be so important, so personal that it would send such a poised a man almost stuttering ? Dark brows furrowed in frustration, and the young woman longed to reach forward, to reassure he could ask anything of her.

But instead of words, he surprised her once more by reaching out and grabbing her hand. Flabbergasted, Ondine froze at the contact of his warm skin over hers. Their magical aura did not clash, but mingled happily, a phenomenon that caused her body to hum in tune with his. It was utterly stunning, and entirely unbelievable; in all their years of camaraderie as student and teacher, he’d never, ever made contact with her body, even though heavy robes.

Ondine felt her heart race and thump, as if it attempted to break out of her chest, and she had to reign in the dizziness to hear his next words.

“What I wanted to say is… Would you be amenable to explore a relationship with me ?”

She heard the words, but they would not register in her mind. So, like a polite British witch, she only managed to squeak a pitiful: “I beg your pardon ?”

 

The answer is final

The corner of his lips quirked in slight amusement, but his eyes remained wary as he took in her features, probably trying to determine her frame of mind. And even though her hesitancy and surprise left him in a torturous place, he refused to use legilimency. Respect demanded he ought to ask, and accept her answer, no matter what it may be.

In this moment, he placed his heart in her hand to be nurtured or crushed. If she so did, Severus knew he would never, ever risk it again. Getting over Lily had been painful enough; he wouldn’t attempt to rebuild himself once more. Her hand felt so small, delicate fingers that could brew the most difficult potion with practised ease and dedication. How he longed for those hands to embrace him, and grant him the greatest present a man could ever ask for; acceptance.

Was he selfish for hoping she would ? Absolutely ? Severus wished his darkness upon no other, least of all the woman he loved. But Ondine had brought him such peace without knowing it, her knowledge of who he has, who he had been complete even before they even met. She had never revered him like a fool, or hated him for being a former death eater; she only granted him the respect her earned in her eyes, and treated him like a human being.

When his past aches resurfaced, causing ill mood to flare, she gave him space.

When he felt witty, she responded with friendly banter. Never crossing the line, but allowing him to take a peek beyond the veil of impossibility. He could see himself by her side, always; for the first time, happiness didn’t feel so out of reach.

She would be the type of woman to support, strategise and understand, not argue against his very nature. Slytherins were cunning creatures; Ondine never sneered at it. Like a true Hufflepuff, she only used her talent without judgement.

Her ocean inheritance granted her a more thorough point of view than the usual human witch; when sometimes, she sighed and confessed how truly desperate she was for her comrades to stop acting like teenagers, he could only marvel that she never behaved like one.

 She truly was a different creature. An enthralling, mesmerising descendant of sirens. And he got caught in her net, a willing victim of her alluring soul.

“Professor ?”

Her melodious voice called him back to reality, to the warmth of her hand that still rested inside his. A good omen, perhaps ?

“Severus”, he automatically responded, wondering when was the last time someone called him by his name other than Dumbledore. Ondine’s eyes opened wide, a window into her bright soul. Was it hope swirling in their watery depth ?

“I asked if you would be willing to further our acquaintance, on a personal level.”

Another wave crashed in their legs, a call back to reality that utterly failed at breaking the bubble they were both ensconced in. He could feel her disbelief; whether because of the audacity of his claims, or her feelings remained unclear. And so, like the courageous man he was, Severus ploughed on.

“You are an amazing young woman, and I will not deny it is selfish of me to taint you with the darkness that resides within me”, he started.

She reacted to this, ready to object, and his heart warmed at her trust but he could not, in good conscience, allow her to deny it. “Do not protest, Ondine. I am what I am, and am glad you know it.”

He would have to unveil his darkness fully, to expose himself… and his former flame for Lily. But not now. There was no use spilling more of his heart if she rejected him.

“You lured me in like the siren you are, Ondine. With you dedication akin to mine, and your abilities to see through the half-blood Prince. You know what I might have to do should HE return.”

And there was no mistaking the shiver than ran down her spine; Severus loathed himself for weighting this declaration with the name of his former master, but she could not ignore he might never be free of his promise. That he might die for it.

And death, right now, seemed easier to face than the next words he had rehearsed in his mind. And then, loosing his usual stoic composure, he squeezed her dainty hand and allowed his gaze to enthrall hers.

“But the truth is, I have fallen in love with you, Ondine. And if you will have me, I am yours.”

Finely shaped eyebrows lifted in an expression of dismay, and tears gathered in her eyes. The sight caused his heart to clench painfully, and when she tugged on his hand to retrieve her trapped appendage, Severus feared all was lost.

Letting go was one of the greatest challenges of his life. When Ondine pinched the bridge of her nose, trying to regain composure, his legilimency skills surged forth in desperation.

He reigned them in with one last bout of sanity, his body shaking from the strain. Eventually, she wiped the moisture from her eyes and took a deep breath.

There it was, the moment of truth.

He expected only rejection, but would hear it all the same, even though his scarred heart was already bleeding.

“I never dreamt…”, she breathed, almost too faintly to cover the noise of the waves crashing around them. Water engulfed their feet, reaching over their knees and yet, they did not move an inch. He remained suspended to her words, awaiting the sentence. Her cheeks reddened as she searched for words; the wait reduced his control to tatters and it was only the grace of her presence that held him aloft. That sweet, accepting aura that always welcomed him even in his foulest days.

“Yes ?”, he eventually asked, coaxing an answer out of her.

“…you would feel the same.”

It was as if a dam burst forth altogether, the floodgates opening to catch him in the whirlwind of a torrent of pent up emotions. Just as the tide of the Cornish sea rushed by them, drowning them to the waist up, Ondine reached for him. His arms wound up around her slight form in a bone crushing embrace, water splashing with such strength that he almost toppled over.

But Ondine just swayed with the flow like the water fairy she was. In this very moment, as her nose was crushed to his chest, and tears sprang from her eyes, he understood.

He understood he'd lost his way so many times before. How Lily, as his first friend, had made him feel safe and valued, even when she purposefully ignored the darkness that swirled within. How he'd never been accepted entirely, always dodging shadows and presenting the front that was required of him.

How, screaming in agony, he'd turned to the dark lord to, at last, get his revenge. To gain power over those who ignored him. The strength to avenge his mother. The bitterness of all those years, unprotected, unbidden, unseen.

But like the sea that now dragged him on the sandy shore, Ondine's energy surrounded him. He was the potion master, the most powerful of ingredient. But like a good brew, his full potential could only be revealed when dropped into the right medium.

She was his medium, the power of water that soaked through every emotion to wash it away. He'd never realised, until now, that she was the only one that could see all of him without flinching. That her energy was the one of acceptance; simply said, she cleaned his soul by simply being. No normal witch could ever be his match.

It wasn't a matter of intelligence, but of nature. He'd needed something different altogether. A gentle soul, a descendant of water fairies, to soothe his aches and push him to accept his potential.

Severus crushed Ondine to his chest with bated breath. To learn she wanted the same… that she held feelings of affection for him ! His hand came to rest upon her spine, feeling her warmth through the sheer linen. A bold move, nearly heretic given they had been teacher and student for seven years. He almost expected her to bolt, but instead, Ondine laughed.

Delighted, Severus scooted backward to watch those features he'd come to adore; her eyes sparkled like dew in the morning. Her hand snaked up his nape, causing shivers to run up his spine. Then she was tugging him down to crush her lips against his.

Stunned, he allowed her to kiss him, the salty undertone of her mouth swallowing his surprise. He almost felt like a rag doll carried in the currents, but Ondine ensured he was safely anchored in the swirling, almost joyful rush of the waves. What should have been triumph felt like sweet surrender, and he willingly succumbed to his water fairy.

He would have no other master.

Ondine eventually released him, dazed, but happy, when the strength of the tide grew too strong to resist. Severus muttered a drying spell under his breath to keep her dress from showing what, he was sure, she wouldn't want to flash to the world.

Not that he was jealous.

"My hand is all sticky", she muttered as wetness returned to the Ocean, trapping the minerals on her skin.

"Then we are stuck together", he murmured in her ear.

The look she gave him was a mingle of awe and playfulness. Her cheeks took on a reddish hue that brightened her beauty to unfair standards, and she smiled.

"For better or worse."

"For better or worse, then, my water fairy."

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