Chapter 1

The Boy Who Lived (But Almost Didn't)

[Author note: This fic is upon request by WRose, who gave me fantastic prompts and I just couldn't resist – I'm mashing up a few of them and I might want to bring in some people from BBC Merlin into it at some point (isn't Merlin just perfect for "the other one"?), but it is primarily going to be a BBC Sherlock – Harry Potter crossover. Of course, Harry and his party are being time-lifted to the future (not by TARDIS, no…although…no, another time) so that he can be a child when he encounters Sherlock and his people.

Here's the original prompt (as you'll see, I'm taking (1) and (3) and mashing it up together:

A Sherlock x Harry Potter crossover where Sherlock rescues harry and adopts him or finds out he's his biological son.

Or they meet 3rd year after he run off.

Or Sherlock finds him on the doorstep ( dursleys)

Or they abandoned the doorstepbaby in London's street. Where the homeless network brings him to Sherlock.]

XXX

"But Aunt Marge suddenly stopped speaking. For a moment, it looked as though words had failed her. She seemed to be swelling with inexpressible anger — but the swelling didn't stop. Her great red face started to expand, her tiny eyes bulged, and her mouth stretched too tightly for speech — next second, several buttons had just burst from her tweed jacket and pinged off the walls — she was inflating like a monstrous balloon, her stomach bursting free of her tweed waistband, each of her fingers blowing up like a salami…"

Harry Potter and the Prisoner of Azkaban

Pandemonium ensued. Aunt Marge floated out of 4, Privet Drive, shrieking at a decibel level well outside of permissible limits. Uncle Vernon yelled at Harry to put his sister right. Harry dragged his school trunk, determined to leave the Dursley household forever. Ripper barked as if possessed. Aunt Petunia banged about in the kitchen, looking for a suitable pan to hit her nephew with. Dudley, with unusual alacrity, fetched his Smeltings stick.

Harry nearly managed to escape. Unfortunately for him, however, Aunt Petunia's well-aimed pan caught the back of his head rather neatly. Dudley pounced on him, wielding his stick. Uncle Vernon, rabid from the loss of his sister, marched back in to find his son whacking his barely-conscious nephew. With a cry reminiscent of an angry bull, Vernon Dursley joined the Harry-punching event until the boy lay still in a pool of his own blood.

"Vernon! Dudley! Stop before you kill him!" Petunia cried.

Father and son paused. Dudley poked Harry's prone form with his stick. No response.

"Is he dead?" Petunia asked.

Vernon felt for a pulse at Harry's neck and felt nothing. He nodded at his wife.

For an instant, Petunia's eyes were sad. She blinked rapidly, however, and glared at her husband. "You need to get rid of the body before those people turn up," she said urgently. "Dudley, wash up and go to bed."

Dudley fled.

Vernon and Petunia wrapped their nephew's cold body in a blanket.

"What about his things?" Vernon asked.

"The owl is gone, but I'll get the rest," Petunia replied. "You put him in the car."

A few minutes later, Vernon Dursley was on his way to London to dispose of his nephew and his belongings.

XXX

Bill Wiggins was moving up in life since his association with Shezza – sorry, Sherlock Holmes. While still technically homeless, he made an attempt to keep himself groomed, and was almost off drugs. After all, he was the Great Detective's protégé, even if the said detective disputed that fact, and he was the one the Homeless Network reported to in Sherlock's absence or when in doubt.

So, it was Billy who received the news of a child's body being dumped near the Battersea Power Station from two little urchins who scouted the area – just a few days after Sherlock was released from his four-minute exile (not that Bill knew that). Since Sherlock despised incomplete reports, Bill sent a quick text to Sherlock and left immediately to meet Ben and Betty at the crime scene to check the facts for himself.

The perpetrator was long gone, of course. Betty had been woken up in the night by a loud noise. She had crept to the corner of the street and watched silently as a large man (size o' a whale, 'e was!) threw out something wrapped in a blanket and a trunk from his car next to the garbage cans and drove off. She had not been able to observe the license plate in the dark. Hoping for something salvageable, she had fetched Ben and the two of them had unwrapped the blanket to find a boy about their age. The boy was dressed in old, blood-soaked clothes too big for him. They thought he was dead, but when Ben had touched the trunk, he'd received an electric shock and the boy had opened his eyes (glowin' green, 't were, Wigs!). Ben and Betty had promptly called Wiggins.

Billy hated domestic child abuse cases, as this one clearly was. The solid trunk with gold lettering of "H. J. Potter" spoke of a well-off, if not rich, family. But the boy's clothes and injuries told another story.

"'E's still breathin'," Ben whispered, as if talking out loud would hurt the poor child.

"Has he said anything?" Billy asked, checking the boy gingerly for signs of life.

Betty shook her head. "'E passed out right after."

"We need to get him to a hospital," Billy murmured. "He's barely alive."

"I believe we can help with that," a deep baritone resonated behind him.

"That's 'im!" Ben cried, excited to meet the Great Detective in person, coat et al.

Fortunately for Harry Potter, Sherlock Holmes detested child abusers as much as Billy Wiggins, and had left Baker Street as soon as he received Bill's text.

"Hello, Shezza," Billy greeted. "Hello, Dr Watson."

John nodded absently and knelt on the road to examine his patient. He cursed. Betty leaned down anxiously, offering to help him.

"Do what you can, John," Sherlock said gently. "An ambulance will be here in two minutes." He turned to Ben. "Show me the trunk."

Ben pointed at the Hogwarts trunk. Sherlock drew a sharp breath. John and Billy looked up at him, surprised. The detective was impossibly pale as he took in the name stamped on the trunk. He reached out to touch the trunk, but Billy stopped him.

"It's electrified," he said. "Ben tried."

Sherlock shook his head and opened the latch without being electrocuted. He rifled through the contents rapidly, searching for a particular object and sighed in relief when he spotted it. He pulled down the lid and refastened the latch.

"There was also an empty bird cage," Ben said, pointing.

Sherlock nodded and turned to John.

"Not good," John replied to the unasked question. "I am not even sure how he is still alive."

Sherlock pulled out his mobile and called his big brother.

XXX

Mycroft Holmes was not a man given to fear – unless, of course, his little brother was involved. He dreaded the days Sherlock called him – for they always meant that his brother's life, health or sanity were in terrible danger. And that was why Sherlock's phone calls to his brother were always answered, regardless of when or where or with whom Mycroft might be.

"Sir, it's your brother," Anthea told her boss, looking into the sterilised room.

Mycroft stretched out his left arm as the right was being stitched up by an annoyed surgeon. The surgeon, however, did not say a word at the interruption. Everyone knew Sherlock Holmes must always take priority.

"Yes, Sherlock?" the British Government enquired.

"Phoenix ashes," Sherlock whispered.

Mycroft closed his eyes and took a deep breath to calm himself. "Are you positive?"

"Yes."

"Text me the location. I will be there shortly. Do not relinquish custody."

"Hurry, Mycroft. Please."

Sherlock disconnected before Mycroft could respond.

"Chopper," the British Government ordered. Anthea nodded and hurried out.

"But Mr Holmes, you must let me dress this laceration before…" the surgeon began.

Mycroft quelled him with a look. "You have until my ride arrives."

XXX

Sherlock re-routed the ambulance, tipped Ben and Betty and sent them off to get themselves a square meal.

"You will catch the bastards that did this, won't you?" Wiggins asked him, his face grim.

"I will," Sherlock promised.

"Good," Wiggins replied, and departed with a salute.

Sherlock knelt beside John and took the boy's hand.

"So you know who this is?" John asked quietly. "I've never seen you this affected before."

Sherlock shook his head. "I know what he is."

"And what is he?"

"What is your diagnosis, Doctor?"

John allowed the deflection and pursed his lips. "Blunt object trauma to the back of the head. Lacerations caused by a long, thin object – perhaps a walking stick. Significant haemorrhage and at least two fractures caused by fists." John stared at Sherlock, his eyes hard. "The child has been used as a punching bag, Sherlock. I am honestly surprised that he's still breathing. Where is that bloody ambulance?"

Sherlock's response was drowned by the sound of a helicopter landing nearby.

The British Government had arrived.

"Mycroft," Sherlock said and sprang up just as Mycroft entered the street with a couple of women in funny robes.

"Ah, Medi-Witches," John said. "Excellent."

Sherlock stared at his friend in shock. "You are a wizard?!"

John met his gaze calmly. "I used to be. Are you?"

"I used to be," Sherlock replied, mimicking him.

Mycroft held up a hand to silence them. "Is the boy who I think he is?" he asked John.

John nodded. "He has the scar. And his name is on the trunk." He turned to Sherlock. "How could you not know?"

"He doesn't know who the Prime Minister is, John," Mycroft said.

John smiled. "Point taken."

Sherlock caught his brother's injured arm. Mycroft's wince did not go unnoticed.

"Who is he?" Sherlock asked. "And what's wrong with you?"

"Harry James Potter, the Boy-Who-Lived," Mycroft replied. "He is known to have defeated the Dark Lord when he was a baby." He sighed. "You can process your data retrieval later, Sherlock. We have to get him to safety for now."

The three men turned to the Medi-Witches.

"He will be fine in a couple of days," the older witch said. "The force majeure magica saved his life and the well-timed healing spells helped his natural magic to kick in. It would be best to keep him under a sleeping spell till his body mends itself."

Mycroft pinched the bridge of his nose. "Sherlock, please tell me you didn't…"

"I had no choice, Mycroft. I didn't know John had performed healing spells," Sherlock replied.

John stared at Sherlock with wide, horrified eyes.

"We will discuss this, little brother," Mycroft promised ominously and led everyone to the waiting car.

XXX

The Medi-Witches left after Harry Potter was successfully installed in one of the guest rooms of Mycroft's townhouse.

Mycroft, Sherlock and John sat in Mycroft's study with generously filled glasses of Firewhiskey.

"Shouldn't you inform the Ministry? They must be looking for him," John told Mycroft.

Mycroft waved a dismissive hand. And winced.

"What's wrong with you?" Sherlock asked. "You have been avoiding my question."

"A minor injury, Sherlock. Nothing to worry about."

"Let John check."

"Unnecessary."

The brothers glared at each other murderously. John sighed and wordlessly shot a generic healing spell at his friend's brother. Mycroft turned his eyes to the doctor, surprised.

"That was…expertly done," he said. "Thank you, John."

Sherlock smirked.

"It's your turn now, Brother Dear," Mycroft intoned silkily. "Give me your hand."

Sherlock shook his head. "I barely use magic. It's not going to drain me."

Mycroft sighed. "You know what happened last time, Sherlock. Your hand, please."

Sherlock extended his hand reluctantly. Mycroft grabbed his brother's forearm and incanted an old spell John could not recognise. Both Holmes' eyes flashed silver for a moment. Then they let go.

"What did you do?" John asked curiously.

"He fixed the magical drain I suffered by performing a force majeure magica on a non-family member," Sherlock replied. "He gave me a bit of his magic."

John was suitably impressed. "They don't teach these things at Hogwarts."

Sherlock smiled. "They don't teach it at Beauxbatons, either."

That answered the question John had been dying to ask. "I can't believe you guys went to France to study!" John said. "What's wrong with Hogwarts?"

Sherlock laughed. "All schools are equally boring, John. We were required to go to Beauxbatons because we are Vernet descendants."

"How did you get to be British, then?"

Mycroft and Sherlock shared a look. "We are related to Emrys."

John could feel his jaw hit the floor.

XXX