'Thanks,' said Ginny, smiling at her.

Harry and Neville stowed the three trunks and Hedwig's cage in the luggage rack and sat down. Luna watched them over her upside-down magazine, which was called The Quibbler. She did not seem to need to blink as much as normal humans. She stared and stared at Harry, who had taken the seat opposite her and now wished he hadn't.

'Had a good summer, Luna?' Ginny asked.

'Yes,' said Luna dreamily, without taking her eyes off Harry. 'Yes, it was quite enjoyable, you know. You 're Harry Potter,' she added.

'I know I am,' said Harry.

Neville chuckled. Luna turned her pale eyes on him instead.

'And I don't know who you are.'

'I'm nobody,' said Neville hurriedly.

'No you're not,' said Ginny sharply. 'Neville Longbottom — Luna Lovegood. Luna's in my year, but in Ravenclaw.'

'Wit beyond measure is man 's greatest treasure, ' said Luna in a singsong voice.

She raised her upside-down magazine high enough to hide her face and fell silent. Harry and Neville looked at each other with their eyebrows raised. Ginny suppressed a giggle.

The train rattled onwards, speeding them out into open country. It was an odd, unsettled sort of day; one moment the carriage was full of sunlight and the next they were passing beneath ominously grey clouds.

'Guess what I got for my birthday?' said Neville.

'Another Remembrall?' said Harry, remembering the marble-like device Neville's grandmother had sent him in an effort to improve his abysmal memory.

'No,' said Neville. 'I could do with one, though, I lost the old one ages ago . . . no, look at this . . .'

He dug the hand that was not keeping a firm grip on Trevor into his schoolbag and after a little bit of rummaging pulled out what appeared to be a small grey cactus in a pot, except that it was covered with what looked like boils rather than spines.

'Mimbulus mimbletonia, ' he said proudly.

Harry stared at the thing. It was pulsating slightly, giving it the rather sinister look of some diseased internal organ.

'It's really, really rare,' said Neville, beaming. 'I don't know if there's one in the greenhouse at Hogwarts, even. I can't wait to show it to Professor Sprout. My Great Uncle Algie got it for me in Assyria. I'm going to see if I can breed from it.'

Harry knew that Neville's favourite subject was Herbology but for the life of him he could not see what he would want with this stunted little plant.

'Does it — er — do anything?' he asked.

'Loads of stuff!' said Neville proudly. 'It's got an amazing defensive mechanism. Here, hold Trevor for me . . .'

He dumped the toad into Harry's lap and took a quill from his schoolbag. Luna Lovegood's popping eyes appeared over the top of her upside-down magazine again, to watch what Neville was doing. Neville held the Mimbulus mimblctonia up to his eyes, his tongue between his teeth, chose his spot, and gave the plant a sharp prod with the tip of his quill.

Liquid squirted from every boil on the plant; thick, stinking, dark green jets of it. They hit the ceiling, the windows, and spattered Luna Lovegood's magazine; Ginny, who had flung her arms up in front of her face just in time, merely looked as though she was wearing a slimy green hat, but Harry, whose hands had been busy preventing Trevor's escape, received a faceful. It smelled like rancid manure.

Neville, whose face and torso were also drenched, shook his head to get the worst out of his eyes.

'S — sorry,' he gasped. 'I haven't tried that before . . . didn't realise it would be quite so . . . don't worry, though, Stinksap's not poisonous,' he added nervously, as Harry spat a mouthful on to the floor.

At that precise moment the door of their compartment slid open.

'Oh . . . hello, Harry,' said a nervous voice. 'Um . . . bad time?'

Harry wiped the lenses of his glasses with his Trevor-free hand. A very pretty girl with long, shiny black hair was standing in the doorway smiling at him: Cho Chang, the Seeker on the Ravenclaw Quidditch team.

'Oh . . . hi,' said Harry blankly.

'Um . . .' said Cho. 'Well . . . just thought I'd say hello . . . bye then.'

Rather pink in the face, she closed the door and departed. Harry slumped back in his seat and groaned. He would have liked Cho to discover him sitting with a group of very cool people laughing their heads off at a joke he had just told; he would not have chosen to be sitting with Neville and Loony Lovegood, clutching a toad and dripping in Stinksap.

'Never mind,' said Ginny bracingly. 'Look, we can easily get rid of all this.' She pulled out her wand. 'Scourgify! '

The Stinksap vanished.

'Sorry.' said Neville again, in a small voice.

Ron and Hermione did not turn up for nearly an hour, by which time the food trolley had already gone by. Harry, Ginny and Neville had finished their pumpkin pasties and were busy swapping Chocolate Frog Cards when the compartment door slid open and they walked in, accompanied by Crookshanks and a shrilly hooting Pigwidgeon in his cage.

'I'm starving,' said Ron, stowing Pigwidgeon next to Hedwig, grabbing a Chocolate Frog from Harry and throwing himself into the seat next to him. He ripped open the wrapper, bit off the frog's head and leaned back with his eyes closed as though he had had a very exhausting morning.

'Well, there are two fifth-year prefects from each house,' said Hermione, looking thoroughly disgruntled as she took her seat. 'Boy and girl from each.'

'And guess who's a Slytherin prefect?' said Ron, still with his eyes closed.

'Malfoy,' replied Harry at once, certain his worst fear would be confirmed.

'Course,' said Ron bitterly, stuffing the rest of the Frog into his mouth and taking another.

'And that complete cow Pansy Parkinson,' said Hermione viciously. 'How she got to be a prefect when she's thicker than a concussed troll . . .'

'Who are Hufflepuff's?' Harry asked.

'Ernie Macmillan and Hannah Abbott,' said Ron thickly.

'And Anthony Goldstein and Padma Patil for Ravenclaw,' said Hermione.

'You went to the Yule Ball with Padma Patil,' said a vague voice.

Everyone turned to look at Luna Lovegood, who was gazing unblinkingly at Ron over the top of The Quibbler. He swallowed his mouthful of Frog.

'Yeah, I know I did,' he said, looking mildly surprised.

'She didn't enjoy it very much,' Luna informed him. 'She doesn't think you treated her very well, because you wouldn't dance with her. I don't think I'd have minded,' she added thoughtfully, 'I don't like dancing very much.'

She retreated behind The Quibbler again. Ron stared at the cover with his mouth hanging open for a few seconds, then looked around at Ginny for some kind of explanation, but Ginny had stuffed her knuckles in her mouth to stop herself giggling. Ron shook his head, bemused, then checked his watch.

'We're supposed to patrol the corridors every so often,' he told Harry and Neville, 'and we can give out punishments if people are misbehaving. I can't wait to get Crabbe and Goyle for something . . . '

'You're not supposed to abuse your position, Ron!' said Hermione sharply.

'Yeah, right, because Malfoy won't abuse it at all,' said Ron sarcastically.

'So you're going to descend to his level?'

'No, I'm just going to make sure I get his mates before he gets mine.'

'For heavens sake, Ron — '

'I'll make Goyle do lines, it'll kill him, he hates writing,' said Ron happily. He lowered his voice to Goyle's low grunt and, screwing up his face in a look of pained concentration, mimed writing in midair. 'I . . . must. . . not. . . look . . .like . . . a . . . baboon 's . . . backside. '

Everyone laughed, but nobody laughed harder than Luna Lovegood. She let out a scream of mirth that caused Hedwig to wake up and flap her wings indignantly and Crookshanks to leap up into the luggage rack, hissing. Luna laughed so hard her magazine slipped out of her grasp, slid down her legs and on to the floor.

'That was funny !'

Her prominent eyes swam with tears as she gasped for breath, staring at Ron. Utterly nonplussed, he looked around at the others, who were now laughing at the expression on Ron's face and at the ludicrously prolonged laughter of Luna Lovegood, who was rocking backwards and forwards, clutching her sides.

'Are you taking the mickey?' said Ron, frowning at her.

'Baboon's . . . backside!' she choked, holding her ribs.

Everyone else was watching Luna laughing, but Harry, glancing at the magazine on the floor, noticed something that made him dive for it. Upside-down it had been hard to tell what the picture on the front was, but Harry now realised i! was a fairly bad cartoon of Cornelius Fudge; Harry only recognised him because of the lime-green bowler hat. One of Fudges hands was clenched around a bag of gold; the other hand was throttling a goblin. The cartoon was captioned: How Far Will Fudge Go to Gain Gringotts?

Beneath this were listed the titles of other articles inside the magazine.

Corruption in the Quidditch League:

How the Tornados are Taking Control

Secrets of the Ancient Runes Revealed

Sirius Black: Villain or Victim?

'Can I have a look at this?' Harry asked Luna eagerly.

She nodded, still gazing at Ron, breathless with laughter.

Harry opened the magazine and scanned the index. Until this moment he had completely forgotten the magazine Kingsley had handed Mr Weasley to give to Sirius, but it must have been this edition of The Quibbler.

He found the page, and turned excitedly to the article.

This, too, was illustrated by a rather bad cartoon; in fact, Harry would not have known it was supposed to be Sirius if it hadn't been captioned. Sirius was standing on a pile of human bones with his wand out. The headline on the article said:

SIRIUS — BLACK AS HE'S PAINTED?

Notorious mass murderer or innocent singing sensation?

Harry had to read this first sentence several times before he was convinced that he had not misunderstood it. Since when had Sirius been a singing sensation?

For fourteen years Sirius Black has been believed guilty of the mass murder of twelve innocent Muggles and one wizard. Black 's audacious escape from Azkaban two years ago has led to the widest manhunt ever conducted by the Ministry of Magic. None of us has ever questioned that he deserves to be recaptured and handed back to the Dementors.

BUT DOES HE?

Startling new evidence has recently come to light that Sirius Black may not have committed the crimes for which he was sent to Azhaban. In fact, says Doris Purkiss, of 18 Acanthia Way, Little Norton, Black may not even have been present at the killings.