If...

Severus did not approach Horace Slughorn the following day. He had no intention of jeopardising his mission by arousing the suspicions of the man who had once been his professor and was now his colleague. Horace Slughorn may not have been the brightest person he knew, but the new teacher thought it wise to be cautious. If Dumbledore believed the Head of Slytherin had vital information, then Severus had to trust him.

When Severus was a student, Slughorn had noticed his talent for Potions and encouraged him to develop it. He and Lily had been the best at it and had worked side by side for five years. In his fifth year, Severus had even been invited to join his professor's illustrious club: the ultimate recognition for a poor boy from Spinner's End. But unlike Lily, who knew how to shine in social situations, Severus had never felt comfortable there. During his meetings, Slughorn entertained prominent people in his office: merchants, researchers, journalists, writers, Quidditch players, duelists, Aurors... Slughorn even counted the founder of a chain of pharmacies and the head of St Mungo's among his acquaintances. Severus had even been pushed by his teacher into the paths of these two impeccably dressed men. Slughorn had sung his praises, extolling his virtues, his creativity. And Severus had been utterly incapable of speaking, of saying a single word to the two men who could have secured his professional future.

Severus had always been a quiet student. He had never known how to put himself forward, and his background was very modest. His mother, Eileen, had made a name for herself by becoming President of the Gobstones Club, a pastime that had been considered corny even when she was a student. At least Slughorn had recognised his talents, even if he had never innovated or carried out significant research. Throughout his academic career, Horace Slughorn had stuck to the same textbooks, never realising the absurdities their authors might have written. He had preferred to surround himself with a circle of brilliant students - especially those from the upper echelons of society - and to organise social gatherings within Hogwarts itself. Slughorn had never been a very attentive teacher to students who did not impress him or who were not related to well-known witches and wizards. But he had seen Severus. Why hadn't that been enough for him, instead of joining the Death Eaters? Why hadn't he played the social game?

*

On Friday, at two o'clock on the dot, Severus returned home from his day of teaching, only to find Sirius Black sprawled out in his armchair, dozing. The nerve of him! He was supposed to be keeping an eye on Lily and Harry, not dozing in his chair. Severus was tempted to hex him on the spot. For once, Black was alone, without his beloved friends who had made Severus' life a living hell. But that would make Severus look like the villain... and it would wake the baby. It was probably time for his nap.

"Am I disturbing you, Black?"

The idiot jerked awake. Even a hibernating bear would have been roused, for Severus had made sure to speak loudly.

"Bloody hell! I thought you were coming back later..."

"And that's an excuse? What are you doing in my chair? And where are Lily and Harry? You're supposed to be looking after them!"

The chair was his and he couldn't bear the thought of Black's backside sitting in it. His presence in the house was already a concession that cost him dearly.

"Calm down," Sirius replied in a nonchalant tone. "One question at a time, eh? I had a few hours of sleep to catch up on, so I took advantage of the little boy's nap to get some sleep. Lily's probably upstairs, or maybe in the attic..."

"I don't care about your excuses!" Severus snapped angrily. "You're not here to sleep or have a good time!"

Hurried footsteps sounded on the stairs, and moments later a young redheaded woman appeared in the sitting room, looking furious.

"What's all this racket? I can hear you from the attic! Harry's asleep!"

"It's not my fault," Sirius defended. "Ask your overly sensitive friend here, who thinks I'm some kind of jailer!"

"A jailer?! Really, Black?" Severus replied indignantly. "Dumbledore sent you here, to my home, to ensure the safety of Lily and her son!"

"Stop bickering!" Lily ordered.

Both men fell silent and lowered their eyes.

"For Merlin's sake!" Lily continued. "You're not children anymore. Learn to be civil to each other."

"He slept in my chair," Severus muttered.

"So what? I'm here, and I always have my wand with me. Would you have preferred him dozing off in your bed? No, I didn't think so. This isn't Azkaban!"

Severus shrank back, while Black looked smug. But his triumph was short-lived.

"And as for you," Lily added, turning to Sirius, "I won't say this twice. Stop upsetting my son before his nap. He's a baby, not a Quidditch Quaffle! What were you thinking, throwing him up in the air when he's supposed to be sleeping? You're lucky he didn't throw up his lunch on you."

"We were just playing..."

Severus sneered. Black really had no sense. Severus may not have had any experience with children before meeting Harry, but at least he knew that much.

"We were just playing," Lily repeated sarcastically. "You have no idea how difficult it is to calm a child down and get them to sleep when they're so excited."

Chastened, Sirius Black mumbled a simple apology. Severus was sure he'd leave, leaving him alone with Lily. But Black decided to linger in his house, even though he claimed he needed more sleep.

"Did you find what you were looking for in the attic?" the former Gryffindor asked with a smile.

"What were you doing in the attic?" Severus asked quickly.

He regretted the abrupt tone he'd used, as well as the question itself, when he saw Lily go pale. He had nothing to hide in the attic, and Lily had already gone there to find a few things to decorate the living room.

"I'm sorry... I should have asked you first. I apologise."

"No!" Severus exclaimed, completely flustered. "I just thought you had already taken everything you needed from there. You can go to the attic whenever you like without asking permission. This is your home."

"Oh!" Lily replied, smiling. "I was just going to see if I could find something to brighten up the hall. I'm not sure what I want to do with it yet. Actually, I wanted to talk to you about a project."

"What project?" Black asked suspiciously.

Mind your own business, Severus thought. That guy always had to stick his nose into things that didn't concern him.

"The hall is really too small. We can't even fit a tiny piece of furniture in there," Lily replied. "I was thinking we could knock down the wall to make the living room bigger."

"That's... that's a good idea," Severus agreed.

"You don't mind?"

"I told you; you can do whatever you like with this house. You can even paint the walls bubble-gum pink if that's what you want."

"Pink? Really, Snape?" the annoying visitor sneered.

Severus shot him a murderous glare. He didn't mean it, of course. He relied on Lily's good taste not to take him literally.

"Haven't you got any sleep to catch up on, Black?" Severus asked with a smug smile.

"I think I'm getting kicked out. What a shame! I was planning on seeing Harry after his nap... With Remus taking over on Monday, only Merlin knows when I'll see him again. He'll probably have grown so much he won't even recognise me.

The tone was indecently whiny and exaggerated. Severus was sure that Black was trying to annoy him and ruin the start of his weekend. He had hoped to spend some time with Lily, talking to her until Harry woke up from his nap. Then he would probably read the child a few articles from Potions Today. After that, the little one would have a little snack while Lily and Severus had their tea.

"Oh, Sirius!" Lily teased. "You've been complaining about being tired all morning. Severus got home early today. You might take the opportunity to get some sleep. And I assure you, you'll be seeing Harry very soon."

Black finally relented after a yawn and left, much to Severus' delight.

"If you ask me, Lily, Black probably had a wild night last night."

"Of course not!" Lily replied indignantly. "There was a full moon on Wednesday night. Sirius stayed up all night looking after Remus, who was in a terrible state. He looked after him again yesterday as soon as he got home. He was really exhausted.

Had Lily not been there, Severus would undoubtedly have made some nasty jokes about Remus' condition.

"It's really uncharitable of you to think such things," Lily continued. "Sirius' nights have been even shorter since he lost... since he lost..."

And Lily burst into tears. What an idiot! Severus cursed himself for not knowing when to keep his mouth shut. When it came to Black, he lost his temper and his mind. Of course, Lily wasn't the only one mourning James Potter; Sirius Black was grieving as well.

"Lily... I'm really sorry. I was stupid."

His friend had turned her back to him and continued to cry. Naively, he'd thought the worst of the grief had passed, but clearly it hadn't. At least Lily seemed to be getting better, no longer spending her days staring out of the window at the rain or watching the rats scurry across the broken pavement. But that was only because she was putting all her energy into renovating the house, distracting herself from her grief. Did she think about it at night when she lay in bed with the lights out? James Potter had only been gone thirteen days. If Lily had died that terrible night, Severus would never have recovered and would have buried himself in the depths of the Hogwarts dungeons.

He hesitated to approach her, but he genuinely wanted to comfort her. Severus had never been very demonstrative, even with Lily, whom he loved more than anything. His emotions - carefully concealed - had betrayed him three times recently: the night he thought he had found Lily's lifeless body, when he had confessed his feelings to her, and when he had comforted her after learning of Potter's hasty burial.

"Lily, forgive me... I was petty."

He heard a few sobs, which made him decide to put a comforting hand on her back. He stroked her gently and Lily seemed to calm down.

"It's so hard," Lily said through her tears.

The hatred for James Potter might never fade, but Severus could easily imagine what Lily was feeling. If James Potter had truly loved Lily, if he had made her happy, then maybe - just maybe, one day - Severus might feel a little respect for him.

"I see," the young man replied.

Lily turned and sought refuge against Severus' chest, clinging tightly to him. It was the first time she had initiated such intense physical contact. She had occasionally held and stroked his hands, but she had never done this since their reunion. He was stunned for a few seconds before he wrapped his arms around her.

"I'm here... Harry's here... and you have your friends."

"I know... I'm so glad you're here with me after all this time."

It wasn't the first time Lily had told him that she was glad to have found him again. But each time he felt a wave of warmth run through his entire body.

"I've really missed you," she added.

"I missed you too... more than anything in the world."

They held each other for a few more moments before Lily pulled away.

"Have you spoken to Slughorn?" she asked, wiping her eyes with her sleeves.

"No, I didn't want to arouse suspicion. He might have found it... odd."

"You're right, I suppose."

The redhead sat down on the sofa and Severus joined her.

"Are you going to follow the plan?"

"I think I've got an idea."

"What's that?"

The idea had come to him that morning while he was teaching the first years, Hufflepuff and Ravenclaw.

"You know, knocking on someone's door for advice isn't really my style," Severus replied. "On Tuesdays, Horace returns to his office around eleven. But he has to pass by my classroom to get there."

Severus had studied his colleague's schedule meticulously.

"And?"

"Right now, I'm in second period with the first year Hufflepuffs and Ravenclaws."

Lily raised an eyebrow.

"Unfortunately, it's a rather weak group, a real magnet for disasters."

"Oh... I see. You want Slughorn to catch you in the middle of the chaos?"

Severus nodded. He was willing to appear weak and desperate to extract information from Slughorn.

"But I plan to mix things up... I'm going to give these students a lesson that's completely different from what's in the textbook, just to make sure they fail at everything from A to Z."

"In short, you want to maximise your chances of having him in your classroom."

"Of course, I'll leave the door open. Slughorn won't be able to resist giving me all sorts of advice, and little by little I'll gain his trust."

"That's devious!" Lily wondered.

"I wasn't sorted into Slytherin for nothing."

Lily chuckled softly.

"I have to admit, your devious side can come in handy sometimes."

It was the first time Lily had ever praised that aspect of his personality. When they were younger, she had seen his cunning as nothing but a source of trouble. And she hadn't been entirely wrong.

"Well, tell me more about your project to knock down a wall."

"Knocking down a partition," Lily corrected.

"Same thing," Severus sighed.

"No, it sounded like you were talking about a massive building site."

Severus sniffed. He could already picture mountains of rubble and dust covering the floor and furniture in the living room.

"Anyway," Lily continued, "I think I can do it magically, but I'll need your help."

"I think we could do it over the weekend," Severus agreed. "So, the living room would be bigger, is that it?"

Lily nodded.

"And a bit brighter," she added.

They talked a little more about their decorating project, then Lily went upstairs to wake Harry and bring him downstairs. The boy's hair was dishevelled, and he was still sleepy.

"This is what happens when you play with Sirius a bit too much," Lily said to her son. "You have a hard time getting to sleep and then you're tired when Sev comes home."

Severus smiled at the child, but Harry didn't return the smile. The boy was slowly waking up, still sucking his thumb and clutching his blankie.

"Perhaps he needed a little more sleep," Severus suggested.

"It's a vicious circle," Lily replied. "If I let him sleep too long in the afternoon, he won't want to close his eyes at night, and he'll be tired the next day."

"I hadn't thought of that."

"I'm speaking from experience. I've made that mistake before," Lily laughed. "At least he'll sleep well tonight. Won't he, Harry?"

The little boy didn't react at all, and Lily set him down on the carpet to play with his toys. Severus had almost suggested reading Potions Today to the child, but such an activity would surely have put him to sleep. Harry needed stimulation. Naturally, Severus sat cross-legged beside the infant and played with him. Gradually the boy regained his energy, babbling, smiling and laughing.

"When will he be able to walk?" Severus asked Lily as he placed a block on Harry's pile.

Severus had only seen him crawl so far.

"He's neither ahead nor behind," Lily replied, stroking her son's hair. "Some babies walk before they blow out their first birthday candle, others wait a few months. He can stand, but he falls easily."

The more Severus looked at the little boy playing next to him, the more he felt contempt for his former master. Harry was just an ordinary baby, one who couldn't even walk on his two little legs. To kill a baby in its crib was utterly senseless, monstrous. How could he ever have agreed to it?

"But he does know how to fly on a broomstick," Lily added with a smile.

"You're joking?" Severus laughed. "Your baby... on a broomstick? I don't believe it."

"No," Lily said, turning her head. "For his first birthday, Sirius gave him a broomstick. I didn't even know brooms existed that small."

"You're telling me something new," the young man muttered.

Toy shops in Diagon Alley weren't exactly Severus' favourite places. He didn't have any children - apart from Harry - in his very limited social circle, and he'd never been taken to places like this when he was younger, not even Muggle ones.

"The first time, Harry nearly destroyed the living room... In fact, the vase Petunia gave me for Christmas didn't survive Harry's first flight."

"You didn't use magic to repair it?" Severus asked with an amused grin.

"It was really terrible," Lily admitted, a little embarrassed. "Petunia and I never shared the same tastes, and that hasn't improved over the years. It was a vase that was both very ordinary... and hideous."

Severus tried to imagine the most hideous vase ever created, but he couldn't.

"I suppose it was meant to be broken," she said more sombrely.

He remembered the carnage - the gaping holes in the walls, the smashed furniture, the jewellery reduced to ashes. The Potter's cottage had been reduced to a field of ruins. Godric's Hollow was a village inhabited by both wizards and Muggles. What had the authorities told the Muggles? Severus didn't know. A gas explosion? A bomb attack? It had become common in recent years.

To distract Lily from her bad memories, Severus asked her for more details about her son's first broomstick. He would never admit it, but before arriving at Hogwarts, Severus had always hoped that he would turn out to be good at flying. But his first lesson had been a disaster. The broom had bucked like a common farm horse, and a Slytherin girl - Momos Flint - had taunted him. A few yards away, James Potter had shown off his flying skills in their first lesson. From that moment on, Severus had taken a dislike to flying on broomsticks, as well as to Quidditch. Fortunately, Severus was now adept at flying any broom, even if it wasn't his preferred mode of transport.

"Well, I'd say the broom was about a metre long, or a bit more."

"And how high could it go?" Severus asked, a little worried.

"Oh! Don't worry!" Lily giggled. "No more than fifty centimetres. As for speed, I thought Harry was flying a bit too fast, but James kept telling me that this broom was a real snail compared to the competition. Anyway, it was enough to break a vase, mess up the living room and scare the cat."

Severus laughed too. There was no doubt that the broom Harry had received for his first birthday had been a wonderful but poisoned gift.

"Normally a broom is meant to be flown outdoors but given the situation we didn't really have a choice. Since when are you interested in brooms?"

"Not really," Severus replied with an enigmatic smile. "I was just curious... I know nothing about toys, at least the ones available in our world."

His parents had been poor, and his father hated magic. Severus had had a few toys during his childhood - a few lead figurines, a teddy bear, a ball, two or three marbles and some cards. Listening to Lily talk about the infamous broom - probably reduced to ashes - Severus realised how much he had been robbed of a wonderful childhood.

"I have to admit I don't know much either," Lily replied. "I was able to visit a few shops at the beginning of my pregnancy, but then I was confined. Our friends sent us lots of parcels, but I had to fight hard to keep our cottage from turning into a toy shop. James didn't understand... It was normal for him, but not for me".

James Potter had undoubtedly had a very different childhood to his own, and to Lily's. His best friend had grown up in a happy home, even if it wasn't exactly overflowing with wealth. The Evans family lived in a much wealthier area than Spinner's End, and their house was much larger than the Snape's. But Severus knew that their expenses were carefully managed and that the girls in the family weren't pampered.

"I want my son to have a happy childhood, but I don't want him to be too pampered, too spoiled," Lily continued. "He will be loved, but I want him to understand the value of things."

"Knowing you, he won't be," Severus replied with a smile.

Severus played with Harry for a while, then Lily took the boy into the kitchen for his snack. The little boy ate a compote and a soft biscuit with great appetite. When he was full, Severus took the child with him to read Potions Today while sipping a cup of tea.

"With any luck, he'll be good at Potions," Lily commented, watching Harry fondly.

"You're extremely talented yourself," Severus replied. "Perhaps he's inherited your skills in that subject."

Lily smiled and put away some books she had found in the attic.

"He's so serious and attentive when you read that magazine to him," she added thoughtfully.

"Honestly, I don't think he understands a word I'm saying," Severus said, turning a page in the magazine.

"That's probably true, but he enjoys it."

The next day, Severus and Lily spent Saturday removing the partition. They spent several hours searching Severus' old books for a spell that wouldn't blow up the wall but came up empty. A new expedition to the attic allowed them to discover a book on household charms and another on magical craft.

"I've never seen these before," Severus said as he handled the second book. "My mother must have hidden them because of my father. There may be some useful things in here."

They opened the books and found all sorts of household spells, as well as a few potions of the same type. Lily was thrilled to read that there were spells for painting walls.

"That's fantastic!"

"I never thought you'd get so excited about a 1920s domestic guide."

Lily stuck her tongue out at him in response, and Severus chuckled. But he was even more surprised when Lily went on to extol the virtues of a potion to unblock drains.

"What have you done with my Lily? Where is she?" Severus exclaimed.

"Idiot!" Lily retorted, punching him in the shoulder.

Severus pretended to be in pain, but soon burst out laughing as well.

Finally, they found a spell that suited their project perfectly, and Lily placed the two books in the library.

Once the partition had been removed without causing any damage, Severus and Lily considered the new layout of the room.

"We could place a piece of furniture near the stairs... to hold newspapers, bills, keys..."

"Why not?" Severus replied.

"And underneath we could store shoes and slippers," Lily suggested again.

Severus nodded and asked Lily where she would find such a piece of furniture.

"In the attic, of course."

"I have a cellar, not very big, but there are some old things down there too."

"Why didn't you say so before?!" Lily exclaimed, already heading for the stairs.

In the cellar, despite the damp, Lily couldn't stop admiring the antiques. A shelf caught her eye, and Severus was ordered to bring it up. Lily joined him shortly afterwards, her arms full of small trinkets. Severus wondered what Lily was going to do with them, and especially where she was going to put them.

"I thought removing the partition would create more space."

"This? It's nothing! Just a bit of decoration. Next week I'll tackle the upstairs!" Lily announced happily.

He didn't have time to say a word as Lily rushed upstairs to wake Harry, who had had a long enough nap. When she came down a few minutes later, Severus heard the little boy babbling happily. And when their eyes met, the child cried out happily, staring up at him with his emerald-green eyes.

"Daddy!"

Severus knew he was in serious trouble. Damn Potter!