Charlie Bone and the Blue Boa. Jenny Nimmo

Bloor stared down at them with cold, pale eyes. Suspicion was written all over his big face with its dull grey skin and thick, bluish lips. ‘Well, I’m waiting.’

      ‘We – er . . .’ Charlie floundered.

      ‘Ah, there you are,’ said a voice, and Mr Boldova appeared behind the headmaster. ‘I’ve been looking for these two,’ said the art teacher. ‘Did you find it?’

      Charlie swallowed, ‘Um . . .’

      ‘That rat’s such a rascal.’ Mr Boldova turned to the headmaster. ‘I brought it along for the children to draw, but it keeps escaping. When I saw these two idling away I asked them to look for it. Any luck, Charlie?’

      ‘No, sir.’

      ‘And now we’re late for our next lesson,’ said Emma meaningfully.

      ‘Dear, oh dear,’ said Mr Boldova. ‘I’d better explain to your teachers. All my fault. Come along, kids. Sorry about this, Dr Bloor.’

      Mr Boldova propelled the two children past Dr Bloor towards the corridor that led to the classrooms.

      Dr Bloor swivelled round to watch them go. ‘That rat must be found,’ he shouted. ‘See to it, Mr Boldova.’

      ‘Of course, Headmaster.’

      As soon as they were out of earshot, Charlie whispered, ‘Thanks, sir. I think we were heading for detention.’

      ‘Keep walking,’ the art teacher said quietly.

      But Emma couldn’t remain silent any longer. ‘We found Ollie,’ she said softly.

      Mr Boldova almost tripped. He gripped the children’s shoulders and said, ‘What? Tell me how – where?’

      As they hurried on to their classrooms, Charlie and Emma took turns to tell the teacher about poor Ollie and his invisibility.

      ‘Ollie’s going to try and get down to supper tonight, sir,’ said Charlie. ‘So you might . . . well, he might be able to talk to you.’

      ‘I can hardly believe it,’ murmured Mr Boldova. ‘Invisible or not, Ollie’s here, and he’s alive. I thought they’d taken him to one of those awful castles of theirs. I’ve spent almost a year trying to find out which one.’

      ‘Do they have many, sir?’ asked Charlie.

      ‘At least five,’ said Mr Boldova. ‘This is so incredible. I shall take Ollie home at the first opportunity. We’ll find a way to cure him when we get home.’

      They had reached Madame Tessier and Mr Pope, who stood fuming outside their classrooms. Mr Boldova quickly explained that he had borrowed Emma and Charlie to search for his rat, Rembrandt, who had escaped from his cage. The two teachers grudgingly accepted his apologies and told the children to hurry along to lunch.

      ‘I’ll see you two at suppertime,’ said Mr Boldova, giving the children a big smile. And he walked away, whistling merrily.

      Would Charlie’s plan for Ollie work? He was sure it wouldn’t be as easy as Mr Boldova seemed to think.

      Runner Bean is rumbled

      On his way to the dining hall Charlie had to pass the portraits. They hung on either side of the long, softly lit passage: haughty- looking women in lace and silk, men in dark robes or wearing velvet coats and white breeches. You might think that Charlie would be curious to know what they had to say but, to tell the truth, he was beginning to find their bad-tempered whispering, rude demands and boring jokes rather tiring. He was also afraid that one of them might come leaping out at him. So he usually tried to avoid looking at them.

      Except for today. Something had jogged his memory.

      ‘Ah, there it is.’ He stopped before a portrait of a bold-looking woman in red velvet. She had dark ringlets, and a necklace of rose-coloured jewels sparkled at her throat. SELENA SPARKS said a small bronze plaque at the bottom of the frame.

      ‘Selena Sparks,’ Charlie murmured.

      ‘What about her?’ Fidelio said over Charlie’s shoulder.

      ‘Ssh!’ hissed Charlie. He waited for a voice, but Selena had nothing to say to him. Perhaps she was shy. ‘I knew I’d seen that name,’ Charlie muttered. ‘All these people are descended from the Red King. So maybe Ollie is too.’

      ‘Ollie who?’ asked Fidelio. ‘I wish you’d talk sense, Charlie.’

      ‘Emma and me . . .’ Charlie began.

      He was interrupted by a shout from Manfred, the head boy. ‘Move on, you two, you’re cluttering up the passage.’

      The boys hurried on, but Charlie, glancing back, saw Manfred stop and stare at Selena Sparks. Charlie hoped Manfred wouldn’t guess why he was so interested in the portrait.

      As they took their places in the long underground dining hall, Charlie whispered, ‘Can you leave a gap, Fido? Someone might want to sit between us. Someone invisible who’s hungrier than we are.’

      ‘Really?’ Fidelio raised his eyebrows. ‘It didn’t take you long to get tangled up in something, did it?’ He moved closer to his neighbour, leaving a small space between Charlie and himself.

      It happened to be one of the best meals Charlie had eaten at Bloor’s; morsels of chicken and bacon floated in a creamy sauce, and he was tempted to eat every scrap, but he pushed a few pieces to the side of his plate, in case Ollie turned up.

      ‘He can have all of mine,’ said Fidelio, who was a vegetarian.

      ‘I’ll have it,’ said his neighbour, a large boy called Morris who played the bassoon.

      ‘No, you won’t,’ said Fidelio. ‘It’s for Cook’s dog. He hasn’t been well.’

      Morris gave him a funny look, then ran his thumb round his own almost-empty plate and licked it. This was against the rules.

      Charlie wondered if Ollie had got lost. He scanned the three long tables, looking for signs of a disturbance. He couldn’t see Emma, who sat somewhere on the Art table. The Drama table was in the middle, and it was by far the noisiest, even though Manfred sat at the head. Apart from Asa and Zelda, who sat on either side of Manfred, everyone in Drama faced away from the head of the table. They perched rather crookedly on the benches, with the shoulder nearest to Manfred slightly raised. No one wanted to be caught by the head boy’s hypnotising stare when they were halfway through a meal.

      Aside from these strange postures, Charlie couldn’t detect anything out of the ordinary amongst the purple capes, so he turned his attention to the far end of the room, where the teachers sat at a table on a raised platform. From here they could keep an eye on the children below them.

      ‘Who are you looking for?’ Billy Raven goggled at Charlie through a fringe of thin white hair. He was sitting on the other side of the table, a few places away from Charlie. His spectacles made his red eyes look far too large for his head.

      ‘I’m not looking for anyone,’ said Charlie. ‘I thought I saw a bat.’

      This wasn’t so unlikely. Hundreds of bats lived in the old building.

      As Billy looked away, Charlie felt something push against his side. Fidelio gave him a surprised look, and then a piece of chicken disappeared from the side of his plate.

      ‘Thanks,’ came a disembodied whisper. ‘Delicious.’

      Several more pieces disappeared, and no one seemed to notice, until Gwyneth Howells, sitting opposite Charlie, gulped, ‘Uh! Your meat just . . .’ and the fork that was halfway to her mouth dropped to the floor, laden with peas.

      Gwyneth bobbed under the table to retrieve her fork and let out an ear-splitting scream. She came up for air, her round, brown eyes starting out of her head. ‘I saw . . . I saw . . .’ she cried. ‘There’s