Prologue

Ginny kissed Albus goodbye.

'See you at Christmas.'

'By, Al,' said Harry, as his son hugged him. 'Don't forget Hagrid's invited you to tea next Friday. Don't mess with Peeves. Don't duel anyone 'til you've learned how. And don't let James wind you up.

'What if I'm in Slytherin?'

The whisper was for his father alone, and Harry knew that only the moment of departure could have forced Albus to reveal how great and sincere that fear was.

Harry crouched down so that Albus's face was slightly above his own. Alone of Harry's three children, Albus had inherited Lily's eyes.

'Albus Severus,' Harry said quietly, so that nobody but Ginny could hear, and she was tactful enough to pretend to be waving to Rose, who was now on the train, 'you were named for two headmasters of Hogwarts. One of them was a Slytherin and he was probably the bravest man I ever knew.'

'But just say-'

'-then Slytherin house will have gained an excellent student, won't it? It doesn't matter to us, Al. But if it matters to you, you'll be able to choose Gryffindor over Slytherin. The Sorting Hat takes your choice into account.'

'Really?'

'It did for me,' said Harry.

He had never told any of his children before, and he saw the wonder in Albus's face when he said it. But now the doors were slamming all along the scarlet train. And the blurred outlines of parents were swarming forwards for final kisses, last-minute reminders. Albus jumped into the carriage and Ginny closed the door behind him. A great number of faces, both on the train and off, seemed to be turned towards Harry.

'Why are they all staring?' demanded Albus, as he and Rose craned round to look at the other students.

'Don't let it worry you,' said Ron. 'It's me. I'm extremely famous.'

Albus, Rose Hugo and Lilly laughed. The train began to move, and Harry walked alongside it, watching his son's thin face, already ablaze with excitement. Harry kept smiling and waving, even though it was like a little bereavement, watching his son glide away from him…

Chapter One

The Foreigner

'Why did you take so long to say goodbye? We'll never find a compartment now.' Rose said haughtily, as she steered Albus down the corridor, checking each compartment as she went. Albus did all he could to stop his jaw dropping, but slipped up a few times. All the goings on around him were so, well, magic. Totally unhidden and extravagant and so open. He was sure at the back of his mind that Rose was saying something, but he couldn't concentrate.

'Well, at least that's what Dad said, but it wasn't in Hogwarts: A History. Mum says that there is so much more to Hogwarts than what's in there, but that it is full of things she found useful so I read it anyway.' she jabbered, not realising he had stopped listening.

'What about in here?' he cut her off.

'Well, somebody is already in there.'

'But they're alone, I'm sure they won't mind.' he said as he opened the compartment door. Rose had been right, there was a lone figure, a girl, with her face hidden behind a book. She didn't look up when they walked in.

'Do you mind if we join you? All the other carriages are full.' Rose asked quietly.

'Not at all,' she replied in a high, sharp voice and she hid further behind the large leather-bound volume. Albus sat opposite her and Rose sat next to him. Albus studied her, she was dressed in all black and had long, waist-length hair which was jet black. On her hands were a pair of black leather gloves and she wore heavy, black walking boots. It looked as if she was in mourning, unless this was the girls uniform, he couldn't be sure.

'So, let's your wand then.' Rose said, obviously trying to pretend the girl wasn't there.

'Here,' Albus extracted it from his pocket and held it up.

'What can you do so far?' she enquired, he could see where this was going.

'Nothing. I haven't tried yet. I thought it was illegal.'

'Well, I don't think minor spells are… are they?' she replied, worriedly.

'I'm not sure.'

'I doubt you will be arrested by the Ministry for something that minor.' Rose jumped and turned to see who was speaking. It was the girl. Albus was smirking at Rose, who scowled at him.

'What did you say your name was?' Rose asked nervously.

'I didn't.' Her face was still hidden behind the book.

'Oh.'

'But you can call me El, if you wish.' she said, softer than before.

'Ok. So where are you from, El?' Rose asked, though she was still on edge.

'Um… I'm from far away, East…' she faltered.

'Oh, okay,' Rose wasn't sure how to react.

'Can you perform any spells yet?' El asked, as if unsure what to say.

'I can perform the Lumos, but I was able to turn our cat green once,' Albus laughed, but El made an odd noise.

'Is there a problem with green things?' She shouted icily. Albus looked shocked.

'No, I just really hate their cat.'

Then the window above where El was sitting blew open, they had been so fascinated by El that they hadn't noticed the rain. El screamed and dropped her book. Rose gasped and El fell from her seat and covered her face with her hands. But James jumped up. He didn't know what was happening. But instinct took over and he slammed the window shut.

'Are you ok?' He turned to look at El, her expression was a mixture of pain and fear. James slowly took in what had made Rose gasp.

Her skin was green.