Malfoy straight in the eye. 'Because if Harry here –' Mr Malfoy shot Harry a swift, sharp look, 'and his friend Ron hadn't discovered this book, why – Ginny Weasley might have taken all the blame. No one would ever have been able to prove she hadn't acted of her own free will ...'

Mr Malfoy said nothing. His face was suddenly mask-like.

'And imagine,' Dumbledore went on, 'what might have happened then ... The Weasleys are one of our most prominent pure-blood families. Imagine the effect on Arthur Weasley and his Muggle Protection Act, if his own daughter was discovered attacking and killing Muggle-borns. Very fortunate the diary was discovered, and Riddle's memories wiped from it. Who knows what the consequences might have been otherwise ...'

Mr Malfoy forced himself to speak.

'Very fortunate,' he said stiffly.

And still, behind his back, Dobby was pointing, first to the diary, then to Lucius Malfoy, then punching himself in the head. And Harry suddenly understood. He nodded at Dobby, and Dobby backed into a corner, now twisting his ears in punishment. 

'Don't you want to know how Ginny got hold of that diary, Mr Malfoy?' said Harry.

Lucius Malfoy rounded on him.

'How should I know how the stupid little girl got hold of it?' he said.

'Because you gave it to her,' said Harry. 'In Flourish and Blotts. You picked up her old Transfiguration book, and slipped the diary inside it, didn't you?'

He saw Mr Malfoy's white hands clench and unclench.

'Prove it,' he hissed.

'Oh, no one will be able to do that,' said Dumbledore, smiling at Harry. 'Not now Riddle has vanished from the book. On the other hand, I would advise you, Lucius, not to go giving out any more of Lord Voldemort's old school things. If any more of them find their way into innocent hands, I think Arthur Weasley, for one, will make sure they are traced back to you ...'

Lucius Malfoy stood for a moment, and Harry distinctly saw his right hand twitch as though he was longing to reach for his wand. Instead, he turned to his house-elf.

'We're going, Dobby!'

He wrenched open the door, and as the elf came hurrying up to