lavatory, K-I-S-S-I-N—”

      “OUT!” Sophie shouted, leaping to her feet, her hands balled into fists.

      Anthony jumped out of her reach. Sophie was just as strong as he was, and she practised her tae kwon do a lot more, so she usually beat him in a fight. “My pleasure. I wouldn’t want to hang round with you two losers anyway!” he flung over his shoulder as he ran away.

      Sophie banged the door shut behind him. Why did she have to have a twin brother like Anthony? He’d been even more annoying than usual the last few days. She knew it was because Grandpa was suddenly doing stuff with her, and Anthony was jealous. Ever since she could remember, Grandpa had spent a lot of time with Anthony. Now she knew that he’d only done so because he’d thought Anthony would be the next Guardian. But the magic hadn’t chosen her twin, it had chosen her. The first girl Guardian ever.

      Thinking of Grandpa’s dour expression as he’d helped her train that afternoon, Sophie straightened her shoulders. I’m going to prove to him that I’m just as good a Guardian as Anthony would have been, she promised herself. Better, even!

      “Look, Soph!” Sam shoved the book across the carpet at her. It was open at a drawing of a round, squat creature with big ears that stuck out sideways, huge flat feet and enormous hands. The title was Thunder Trolls. But Sophie wasn’t reading the title. She was looking at the four-line verse that Sam was pointing to at the bottom of the page. She read it out:

      “High in an old place

      The yellow gem can be found

      Hidden on a dusty shelf

      Strange wares all around.”

      “The yellow gem!” Sophie gasped, meeting her best friend’s excited eyes. “Sam! You’ve found one of the five clues!”

      Sophie and Sam both re-read the clue. “So the yellow gem is hidden on a shelf somewhere old,” mused Sophie, chewing the end of her long blonde ponytail.

      Sam frowned and rubbed his chin. “But loads of buildings around here are old. That doesn’t help.”

      He pointed to the last line. “‘Strange wares all around.’ What does that mean?”

      Sophie made a wild guess. “Maybe wares are things you wear? So the gem might be in a wardrobe, or in a clothes shop…”

      Sam shook his head. “I’m sure ‘wares’ doesn’t mean that. I’ve heard the word before, I just can’t remember what it means.”

      They looked at each other, puzzled. “I know – the dictionary!” Sophie raced for her desk, but couldn’t find it anywhere. Then she remembered that she had let Mrs B have her dictionary for a jumble sale a few months ago, because she never used it. “Oh, how can we work out what it means?”

      “Just keep thinking,” said Sam.

      Sophie thought all afternoon and all evening, but she didn’t come up with any good ideas. She couldn’t even ask Grandpa about it because he was out that night and then went running in the morning. Never mind, she thought as she got ready to leave for school. Sam and I can talk about it today. Maybe he’s found a dictionary and has worked the clue out.

      “Have you got your school bag, Sophie?” checked Mrs Benton. She had grey hair and rosy cheeks.