Chapter 1: Mistaken Identity

The sound of the old man's flat feet slapping hard on the stone floor echoed through the corridor and alerted the black-haired boy to his approach. The boy pushed up his glasses with a grin. The chase was always the best part. He waited until he could hear the labored breathing then ran. The old man turned the corner and he saw the boy halfway down the corridor.

"Potter," Filch wheezed. He hurried down the hall. Through the sound of his own breathing and his feet hitting the floor, he could make out the sound of the boy running ahead of him. He also heard the boy laughing. Ducking into a secret passage, Filch cursed the students and hurried around the bend and up the stairs. He appeared as if by magic in the corridor just in front of Harry Potter. "Got you this time, boy!"

"What?" Harry squirmed in Filch's grip but couldn't pull free.

"Thought you could get away with it, eh?" He marched Harry back the way the boy had come, straight to the Headmaster's office. Any protest the boy made fell on deaf ears and Filch threw him into the chair before the Headmaster with surprising strength for a man as seemingly frail as he was.

"What appears to be the problem, Argus?" Albus Dumbledore asked with interest.

"Caught Potter red-handed, I did," Filch said with triumph. "He was breaking into the storeroom on the third floor."

"I was not!" Harry protested, Filch just sneered.

"I'm afraid, Argus," Dumbledore said and the caretaker's face fell, "Harry could not have been the student you saw. He has been in private lessons with me since six this evening."

Filch shook his head. "No, Professor, there's no mistaking it. It was Potter. I saw the hair and the glasses and the strut."

"I do not strut!" Harry was sick of the crabby old caretaker and Potions Master insisting he strut about the school as his father had. Of all the things Harry had inherited, a cocky strut was not one of them.

"Quite right, Harry," Dumbledore assured him. "You may return to your dormitory."

Harry stood and demonstrated just how much he did not strut as he walked from the office. Argus remained to argue with the headmaster. There was no other boy at Hogwarts that looked like Harry; it had to have been him.

The sixth year boy walked through the corridors toward his dormitory. He had been with Dumbledore looking at a memory of Tom Riddle's mother. It was their first lesson and it had certainly not been what Harry had been expecting, which he should have expected since he was dealing with Professor Dumbledore. The crafty old Headmaster was always surprising, and not always in a good way when it came to Harry and his destiny.

He knew the old adage that 'knowledge is power' but he found it hard to believe that a few memories about the family and life of Voldemort could yield enough knowledge to help defeat him. Now he had Filch accusing him of stealing on top of his confusion, and his bloody cat shadowing him through the corridors.

"Go away!" Harry told the cat. She didn't listen. She never did.

His Godfather told him a story of how Harry's dad had once charmed the cat to think there was a dog barking whenever it came near him or his friends. The cat would leap into the air and run for cover, allowing James and the Marauders to play whatever mischief they intended without worry of the cat bringing her master down on them. Harry would have liked to learn that charm. He wasn't one for mischief, but he was often forced to break the school rules to do the right thing.

But Sirius was dead and with him died Harry's hope of a family and all the man's memories of Harry's father. They had spent so little time together. It was all Voldemort's fault. Harry hated that wizard. He took Harry's parents, his home and now his Godfather, too. He wanted nothing more than to see that evil bastard gone from this world.

Someone, a boy by the sound of it, laughed loudly just around the corner. The cat ran ahead of him and disappeared around the bend. Mrs Norris, the cat, wouldn't have left Harry if the boy who laughed wasn't someone far more troublesome. He hurried to the end of the corridor and turned left, too, trailing the cat as she had him. Her fluffy tail was easier to follow than the Golden Snitch on a sunny day. It bobbed around corners and through hidden passages. The cat was fast, but so was Harry. So, apparently, was the boy Mrs Norris was after. Harry could hear the boy running and laughing, always just up ahead or around a corner.

In the long corridor that ran the length of the school from North Tower to South, Harry finally saw the boy. He had tripped over a suit of armor that was migrating from one side of the hall to the other and had fallen onto the stone floor. Mrs Norris was on him in an instant. Harry was a bit behind her. The boy sent the cat flying with a wave of his wand.

"Bloody cat," he muttered and stood to dust himself off. He stopped when he saw Harry and studied the approaching sixth year with a cocked eyebrow and tilted head.

Harry was confused. The boy looked just like him. He wore glasses and wild black hair. His Gryffindor uniform was slightly loose because he was as skinny as Harry was. If Harry had a brother, he would look like this boy. But as Filch said, there were no boys at Hogwarts who looked like Harry.

"Who are you?" Harry asked, slightly out of breath from the jog and the shock.

"I could ask the same thing," he replied, sounding very much like Harry, only far more confident. He walked forward with a distinct swagger to his step.

"You could, but I asked first." Harry said.

"Very mature, kid," the boy smirked.

"Who are you?" Harry demanded. "You don't go here."

"Do so. Have for five years, but I've never seen you before."

"I could say the same thing," Harry stole the boy's words, which made him smirk again.

They both jumped as a loud crashing noises came from down the corridor. Someone, most likely Filch, collided with another of the wandering suits of armor. He was much closer than Harry would have expected.

"Shit!" the boy cursed. "I'll finish with you later, kid." He pointed at Harry and took off running. Harry wanted to follow, but he had already been accused by Filch once tonight and didn't care to have it happen again. If he were caught Dumbledore wouldn't be able to vouch for him this time. He ran in the opposite direction, back toward his dormitory.

It was late when Harry finally made it back to Gryffindor tower, where his friends were waiting to hear how his first lesson went. They had all expected him to be learning secret spells, not diving into old memories. As interesting as it all was, Harry was far more intrigued by the sudden appearance of a boy who looked and sounded almost identical to him. This boy, whoever he was, was going to get Harry into serious trouble.

"I bet it's Malfoy," Ron said.

"How do you reckon?" asked Harry.

"The way I figure it," Ron said slowly. "You-Know-Who wants you dead, but when you're at school he can't touch you. We know Malfoy is up to something, something big and something for You-Know-Who. What if his plan is to get you expelled so that You-Know-Who can come and get you?"

Harry didn't like the sound of that. "How does that boy fit with that?"

"Polyjuice Potion obviously," Ron said. "He found some bloke that looks just like you, stole his hair and is running around the school getting you in trouble with Filch."

"Maybe…" Harry considered it. "What do you think, Hermione?"

He looked up from his seat on the carpet and saw Hermione's nose stuck in her book. It wasn't unusual, but she normally spared them some attention. Now that he thought about it, she had been uncharacteristically quiet while he told them about his private lesson with Dumbledore, too. She had read through everything he said.

"Hermione!" he shouted.

The girl jumped and nearly dropped her book. She looked around, confused, and saw him sitting on the carpet by her feet. "When did you get back?"

"An hour ago. Where've you been?" Ron asked.

"Oh," she looked between them and saw they weren't joking. "I was just reading."

"We noticed," Harry said.

"Well, it's a dreadfully fascinating book," she said quietly. "I didn't expect much with it being a Muggle book and all, but it's quite amazing. Like folktales."

"Did you hear anything I said?"

She bit her lip, embarrassed. "No. But I'm listening now!"

Harry sighed and went through the whole night start to finish again. She, like Harry, was equally as intrigued by the boy who wasn't Harry. She demanded he describe the boy's appearance in exact detail, especially how he differed from Harry. That was a short list of features, as really only the color of his eyes, the shape of his nose and his confidence ('a damn cocky git' were Harry's exact words) were different; everything else was the same as far as Harry could tell. Hermione knit her brow in thought, but could come up with no explanation better than Ron's.

That ought to have been the first clue that something strange was happening at Hogwarts.

"We'll just have to keep watch on Malfoy," Hermione said.

"We already are!" Ron reminded her in a very annoyed tone.

"I mean specifically tomorrow," she sighed. "If he's extremely pleased with himself tomorrow at breakfast, then we know it was him or one of his goons under the Polyjuice Potion."

"It would have been him," Harry said with absolute certainty. "Crabbe and Goyle don't strut."