Harry Potter and the Daughter of Poseidon

Harry Potter - J. K. Rowling Percy Jackson and the Olympians - Rick Riordan
F/F
F/M
G
Harry Potter and the Daughter of Poseidon
Summary
In the original fic, Hermione and Ron warn Harry that Mara can't be trusted because she is a Slytherin and her name is Mara which according to Hermione means 'bitter'. While Mara may be 'bitter' in Hebrew, it actually means 'of the sea' in Irish.Ignoring his friends, Harry befriends Mara and finds out that Hermione was actually wrong for a change.Is there more to Mara and the potions accident?
Note
This is a Hold for the End for what happens after Episode 114 'All that Love can be' of Fanatical Fics and Where to Find Them podcast.Written for the Fanatical Fam's Hold for the End Please Writing Competition 2025The Harry Potter and Percy Jackson characters do not belong to me, nor do the lyrics of ‘All love can be’ by Charlotte Church.

‘You’re a child of the sea,’ my mother used to whisper in my ear every night as she tucked me in to sleep, before she sent me away.
I never knew my father, and as a small child I sometimes imagined that I literally just rose up from the sea, fully formed. I know how silly that sounds.’
Mara looked away and Harry kindly touched her hand.

‘I never knew my parents, so I know what it is like to try to picture where you came from, especially if no one tells you about your past.’

‘What was you mum like?’ he asked kindly.

‘Sally? I haven’t seen her since I was about three years old. Aunt Mer is more of a mum to me really.’

‘Mer, as in French for the sea?,’ Harry asked curiously.

Mara laughed.

‘Impressive knowledge, given that there are no foreign languages thought at this school.’

Harry blushed, he hadn’t meant to show off.

‘It's short for Meredith,’ Mara continued, ‘which funnily means protector of the sea, so what better guardian for a child of the sea.’

Mara’s half-hearted laugh didn’t quite disguise the heartbreak she was feeling and Harry awkwardly gave her hand a little pat.

Mara was very easy to talk to.
How could Hermione say that everyone hated her?
Clearly not everyone hated the new girl. Harry himself being a case in point.

~ ~ ~ ~ ~

Having been the proverbial fly on the wall in Dumbledore’s office had been quite an eye-opener.

Thank Merlin for his Dad’s invisibility cloak.

What was the old headmaster up to this time. Harry would bet his Firebolt that Snape was already perfectly fine somewhere in the castle, no doubt tasked with some secret mission, why else lie to Mara about how long it would take to restore Snape? Ten years, what rubbish.

Harry guessed there was more to Mara and the spell-mishap and he was determined to find out what the story was behind the Slytherin-turned-Ravenclaw transfer student.

~ ~ ~ ~ ~

‘Don’t you think you should have told her the truth?’ Snape, none the worse for wear, queried the headmaster.

‘Tell her that she isn’t a wizard, has no magical powers, is in fact the half-blood offspring of one of the most powerful Greek gods and is being hunted by monsters that can smell her a mile away?’ Dumbledore scoffed.

‘How do you think she would have received that news?’

Snape didn’t answer.

‘At least the protective spells guarding Hogwarts and the combined wizarding powers of the staff and students should mask Mara’s emerging powers sufficiently,’ Dumbledore continued.

‘I hope you are right, we wouldn’t want to endanger the rest of our students unnecessarily,’ Snape remarked sarcastically.

‘That’s why it is fortuitous that you are now believed to be no longer with us, Severus. You can keep an eye on her while she is here. Disillusionment Charms and Invisibility spells are no problem to you.

‘And who is going to take over my lessons while I am gone?’ the potions master asked.

‘Why, me of course, you don’t think I am up to the task, Severus?’

Snape knew better than to answer that challenge.

Not for the first time he wondered why he always ended up caught between meddlesome men and in this case Greek gods.

And how did he always end up as a glorified babysitter? First Potter and now Mara. He wasn’t a bloody Satyr.

~ ~ ~ ~ ~

Mara’s euphoria about being sorted into Ravenclaw was short-lived.

As they left Dumbledore’s office they overheard some Ravenclaw students voicing the same sentiment as Hermione,

Mara looked at Harry with such a look of misery that all he could do was wrap his arms around her.

He knew what it was like to be ostracised by the entire student body, when everyone thought he had put his name in the Goblet of Fire.

‘It will all be alright,’ he said to Mara, giving her shoulder a squeeze.
‘You will have at least one friend in Ravenclaw. Luna is a good friend of mine and she's the most accepting and caring person I know.
And if I know anything about the Ravenclaws it is that they are pragmatic. Soon you’ll be nothing more than a puzzle that needs solving.’

‘I am not sure whether that thought is comforting or terrifying,’ Mara replied.

~ ~ ~ ~ ~

Luna got all excited about the fact that they were both named after forces of nature, the sea and the moon, and how the phases of the moon affected the tides.

She told Mara that crabs, mussels, starfish, snails and other sea creatures rely on the tides, and therefore the moon, for survival.

‘So the world actually needs us both,’ she said to Mara in all earnest.

Harry had been right, Mara thought, as she smiled gratefully at the unusual girl.

~ ~ ~ ~ ~

When Mara made her way to Ravenclaw tower that night, she was slightly apprehensive about the riddle she would have to solve to get into the common room.

The corridors were deserted.

Something was making her hairs stand on end. Was someone watching her?
She stopped and looked around her, nervously.

Snape, who had been following her, also stopped in his tracks.
He would have to be more careful.

As he watched her continue on her way, he couldn’t help feeling that he wasn’t the only one watching her and he was sure it wasn’t Potter under his invisibility cloak. It was someone or something more sinister.

Boy, oh boy, what trouble had Dumbledore gotten them into this time. As if the Potter brat hadn’t been drama enough.

~ ~ ~ ~ ~

When new, she can't be seen at all
But she grows with each night fall
And as she looms over the wall
Hark and hear the lone wolf's call

‘Luna’ was the first thing that popped into Mara’s head.

Luna Lovegood, the name alone gave her a warm fuzzy feeling.
With her long blonde hair, gorgeous blue eyes, that looked at the world in wonder and not to mention those sensuous lips.

Mara blushed profusely before quickly blurting out the answer to the riddle: ‘The Moon’.
Grateful to have solved the riddle, she entered her new home away from home.

~ ~ ~ ~ ~

‘Ah, young love,’ Snape mused, unknowingly echoing the same sentiment as the headmaster up in his office, thinking of Harry under his father’s cloak.

‘The heart wants, what the heart wants,’ Snape thought morosely. ‘Bloody love triangles.’

He could no longer sense the hidden force he had detected earlier, but there had undoubtedly been something before and he thought Mara must have sensed it also.
He did not think his presence alone could have evoked such sense of unease in the girl.

Of course Neville Longbottom would have disagreed with Snape’s assessment entirely. Even the mention of Snape’s name would have turned the Gryffindor’s legs to jelly not that long ago.

So what creature could move in the shadows and could have penetrated the castle without setting off any alarm bells, Snape wondered.

Maybe it was time for Dumbledore to have a chat with that facility where the girl’s twin brother was being schooled, or trained, or something.

~ ~ ~ ~ ~

In his office upstairs, Dumbledore had the same thought as he threw an old gold coin into his pensieve.

The pensieve briefly took on the image of a rainbow before a connection was established with a gentleman who appeared to be in a wheelchair.

‘So, it is true then,’ the man said by way of greeting.

‘If by true you mean that I may need your help, then yes,’ Dumbledore replied.

The man laughed.

‘A cautious man like myself, I see. My name is Chiron, I am the activities director for Camp Half-Blood.

‘Dumbledore, headmaster of Hogwarts School of Wizards and Wizardry. Pleased to make your acquaintance.’

The pleasantries over, the two men went down to discussing the problem at hand.

‘I’m not blaming Sally, Mara’s mum, but it would have been a lot easier to protect her here, especially given the prophesy,’ Chiron said.

‘Don’t start me on prophesies,’ Dumbledore replied, ‘we have another pupil here who is the subject of a prophesy. Messy things, prophesies. So many unknowns and interpretations and why does someone always have to die so the other can live.’

Chiron laughed.
‘I see your problems are not so different from mine.’
‘As for fighting whatever will be coming after Percy’s sister, celestial bronze weapons are what works best.’

‘I’m not sure we have celestial bronze, but we have Goblin silver weaponry and we have an array of statues guarding the castle that can be brought to live with a simple spell.’
Minerva would be in her element, Dumbledore thought, she loved that spell.

‘That sounds like fun,’ Chiron said and meant it.
Of course bringing statues to live wasn’t unique to the Wixen world, he thought, though maybe wizards were not aware that these statues were really automatons that could be activated with a simple command sequence.
‘It’s a pity you don’t have a mechanical dragon guarding your castle,’ he said.

‘Oh, if need be we can have a dozen real dragons here from Romania in no time. I would just have to send an owl,’ Dumbledore explained. ‘Hogwarts was host to four of them a few years ago. When trained properly they are quite remarkable creatures.’

The conversation was turning into a ‘My wand is bigger than yours’ competition.

‘My real concern is that we've no real idea what or who we are likely to face when it comes to it, Dumbledore finally brought the discussion back to the real issue at hand.

‘Join the club, my friend,’ Chiron laughed.

‘The likelihood is that there are very few potential threats in your neck of the woods as most of the action will be focused on this part of the world as both the entrance to Mount Olympus and the entrance to the Underworld are currently on this continent.
You probably only have to deal with some hellhounds.’

‘Some what?’ Dumbledore asked, but before he could get an answer the connection was gone.

‘A golden drachma doesn’t get you much these days,’ Dumbledore sighed.

~ ~ ~ ~ ~

‘Some hellhounds?!’ Snape exclaimed, when he met up with Dumbledore later that evening.

‘Where is Padfoot when you need him,’ he grumbled.

‘And where do we get celestial bronze weapons?’
‘I already sent some of the portraits to check out some of the museums,’ Dumbledore said.
In the meantime, Godric’s sword will have to do.’

‘He’ll probably turn in his grave at the thought of a Slytherin wielding his sword to save a Ravenclaw.’

‘Now, now, Severus, you make it sound as if the founders were only protecting their own.’

~ ~ ~ ~ ~

In her room in Ravenclaw Tower, Mara was oblivious to all of this and had a most wonderful dream of a man with a trident softly singing a song, while rocking two shell-shaped cradles.

The love and protection of the words penetrated her subconscious and she knew that this was her father. The cadence of the song reflected the waves of the ocean.

I will watch you in the darkness
Show you love will see you through
When the bad dreams wake you crying
I'll show you all love can do
All love can do
I will watch through the night
Hold you in my arms
Give you dreams where no one will be
I will watch through the dark
Till the morning comes

~ ~ ~ ~ ~

Elsewhere, in the dark recesses of the castle, a hellhound also slept peacefully. Mrs O’Leary had followed what she thought was Percy’s scent through the deepest parts of the earth, only to find that it wasn’t him, but his twin. She had watched the girl for a while and sensing that there was no danger from any of the mortal beings, even those that were hiding from Mara, she had fallen into a deep sleep. Shadow travel was exhausting. She would make it her mission to protect Mara with her life until such time that she would choose to reunite with her brother.