Thank you to all you lovely people who read, reviewed, favourited, and added this story to your alerts

Wonderfoal: Thank you, no I haven't seen the Mirror of Erised used either. To put your mind at rest this fiction is severely AU everything which happened in the Marauder Era happened a few years earlier than it did in the real story.

Disclaimer: See Prologue

Robyn Lily Potter lay awake in the fifth year girls' dormitory. The Gryffindor Quidditch captain hadn't been sleeping well recently since she was plagued by memories of the night her family had been torn apart. It was coming up on ten years to the day that her poor baby brother had been killed.

This was one of the few things she couldn't tell anyone about- no one, not even Will, Teddy and Percy understood her guilt over what happened that night. If she'd only been more careful mum wouldn't have had to take her to St. Mungo's and that rat Pettigrew wouldn't have been able to betray them to Mouldyshorts. She knew it wasn't her fault- she'd only been five at the time, but she still blamed herself for what happened.

Robyn pulled out the Marauders' Map and tapped it with her wand as she did many a night when sleep alluded her.

"I solemnly swear I am up to no good" she whispered

The map spread itself over the aged parchment.

After finding the map in the first term of their first year Robyn and the other two self-styled heirs to the map; William Black and Terrance 'Teddy' Lupin had taken up the mantle of Marauder-hood. Their fourth Marauder (Percy Weasley), had joined them at the end of first year when he'd finally come down off his high horse and got the wand pulled from his arse.

The map offered no entertainment; it seemed that not even the ghosts were on the corridors that night. Sighing Robyn raised her wand to pronounce her, "Mischief Managed" when something caught her eye- a new dot appeared on the page, in a small room near the library. The label attached to the dot filled her with shock- could the map have become faulty?

She knew very well that the map never lied but the name on the label affixed to the new dot was a name that Robyn knew was no longer attached to a living person.

The dot was labelled 'Harry Potter'

"Ok, so we're up" Teddy Lupin grumbled mutinously as he, Will and Percy flopped into armchairs by the fire. "What's all this about?"

"Either there are some very strange things afoot" Robyn, who was running her free left hand through her long red hair. "Or the map's malfunctioning"

Instantly the three male Marauders became alert.

"What makes you say that?" Will asked, his eyes leaving his crush to settle on the map clutched in her right hand

"Because there was a name on the map which shouldn't be there" she replied. "It just sort of appeared there, in a room near the library"

"What name?" Percy asked

Instead of answering verbally Robyn spread the map on the between them and pointed to the room in question.

"Merlin's Beard!" Percy gasped

"Strewth!" Will gaped at the parchment. "That's impossible"

"Sorry I threatened to curse you" Teddy told her. "You were right, this is serious"

"I'll go grab the cloak" Robyn announced. "We need to check this out"

He was lying spread-eagled on a stone floor. He'd been lying there, with his eyes shut trying to make the world stop spinning. He squeezed the silken fabric of the invisibility cloak. He clutched it as if it were the only thing he could trust.

Finally he decided that it was time to open his eyes. To his astonishment, and slight disappointment he was lying in the very same room as he had been before his run in with the mirror. Now, strangely, it was the door which stood before him. One heart stopping moment later the handle started turning.

Harry promptly shut his eyes again. He heard four lots of footsteps.

"Stone the crows" a male voice exclaimed. "At least we know that the map isn't malfunctioning"

"Do you reckon it really is him?" a second voice asked, from somewhere over Harry's head. "I mean the map never lies, but do you reckon it's possible to fool it?"

"Not a clue Will" a third, familiar, voice replied. "Robyn, have you still got the… Robyn?"

"She's in shock" the second voice announced. "And hardly surprising really is it, Will?"

"Lay off him Ted" a female voice, Robyn's apparently, chastised quietly. "S'not like he really understands… Will, here"

There was a rustle of parchment and, the first voice, Will's, declared. "I solemnly swear I am up to no good"

Harry wondered the purpose of the boy, Will's, words but, feigning unconsciousness he couldn't question them.

"Still says it's him"

"How… how's that possible?" Robyn asked. "He's gone…"

"The map must be wrong!"

"No Perce the Map never lies, remember"

In that instant Harry knew where he recognized the familiar voice from- it was Percy Weasley's. Why was Percy out after hours? What was all this about a map? What the hell was going on?

"I'll wake him up" Will's voice declared. "Aguenti!"

A jet of water to the face had Harry sitting up, gagging on the water which got in his mouth and up his nose.

"Will, stop, he's awake" Robyn's voice put in, mercifully.

Will did as he was told and Harry wiped his eyes. He opened them to find four pairs of legs in his line of sight, looking up his jaw dropped. Each of the four figures towered over him- even Robyn, who was the shortest of the four was a good deal taller than him. Robyn was beautiful, she looked familiar- sort of like his mother, only with dark red hair and hazel eyes, much like his fathers. To her left stood Percy Weasley, only he didn't look like the Percy that Harry knew, his hair was unruly and he wore no glasses. Peering over his shoulder was a boy with vibrant blue hair, which grew lighter the further away from his head it got- his eyes were amber. On Robyn's other side was a tall handsome dark haired boy with pale blue eyes.

Robyn took a step towards him and said, nervously.

"Harry?"

Robyn was no coward- she was a Gryffindor, a second generation Marauder, and wannabe Auror; but the sudden arrival of her baby brother, a boy who had been dead for the past ten years was too much to handle. Had she been alone she would have stunned him and run, but her three greatest friends gave her strength. She took a tentative step towards the boy.

"Harry?" she asked. "Are you Harry Potter?"

"Yeah" Harry nodded, surprised that they didn't know who he was- everyone else did. "Who are you?"

"My name's Robyn" she told him, she didn't like how small he was- he looked half starved. "These are my friends; Will Black, Teddy Lupin and Percy Weasley"

"Ok" Harry nodded, his green eyes, so like their mother's bored into her hazel ones. "But I still don't know who you are"

Robyn blinked. She knew it was irrational but Harry's words had stung- she remembered the baby he'd been, always wanting her to play with him, in the absence of Teddy and Will she had always obliged him. Here he was ten years later, with no memory of her.

"Harry, I'm- I'm Robyn Potter- your sister"

Harry's green eyes widened and rolled back in their sockets as he fell back in a dead faint.

~V~

And thus Harry is found...

Yes the three Marauders that people actually like all have a kid in the same year :).

This version of not Tonks' son- as much as I like the Remus/Tonks pairing it won't work here- You'll find out about his and Will's mothers in a later chapter.

I have nothing against Percy- I think he gets a bit of a rum deal in the books: in this story he isn't nearly so anal; I've made him sort of like young Remus only without the 'furry little problem'.

Please R&R (No flames please)