The twins dumped their bags in their lockers and headed for the Science room. Although they were earlier than usual, there were still plenty of students and teachers about. Max knocked on the door of the lab and poked his head around.

‘Hello? Mrs Vanden Boom, are you here?’ he called, as the pair walked inside.

They were just about to leave when Kensy spun around. ‘Did you hear that?’

A muffled noise seemed to be coming from the cupboard at the back. Max turned the handle and pulled the door open. The children were stunned to see Romilly Vanden Boom stumble out of the dark space.

‘Oh, thank heavens you two came along.’ The woman grabbed hold of the nearest bench in an effort to regain her balance. She pushed a loose strand of curls away from her face and straightened her lab coat. ‘I’m running frightfully late.’

‘What were you doing in there?’ Kensy asked, peering inside what appeared to be a supply store.

‘I’ve told Magoo for years that we need to get a closer on that door. Once the silly thing shuts, it’s impossible to pick the lock from the inside. It’s not the first time I’ve been stuck and it won’t be the last, but I’m very glad you two found me. I’d never have got all my prep work done before class,’ the woman said. She looked expectantly at the children. ‘Now, I presume you didn’t just come to rescue me?’

‘I was hoping you might be able to help me with my watch,’ Kensy said, removing the timepiece and handing it to the woman. ‘I think it’s the battery and you have all those fancy tools. I didn’t want to bother going to a jeweller if I could fix it myself.’

The Science teacher smiled. ‘Well, I can give you a minute – think of it as repayment for springing me from the cupboard.’

Kensy and Max followed her to the long bench at the front of the room.

Mrs Vanden Boom turned the watch over in her hand and studied the back, then picked up a large magnifying glass. ‘Impossible,’ she muttered. ‘This looks just like an MK 13.’

Kensy and Max wondered what she meant. There were a lot more mmms and ahhs, but the teacher didn’t say anything else for quite some time.

‘Can you see what I need to do with it?’ Kensy asked.

The woman shook her head. ‘It’s the most curious thing. Where did you get it?’

Kensy looked at her brother. Perhaps this hadn’t been the best idea. Mrs Vanden Boom was still scrutinising the timepiece intensely. Max pulled his cuff down over his own watch.

‘For my birthday,’ the girl said. ‘It was a present. I think it must have come from Australia.’

‘Would I be able to hold on to it for a little while?’ the teacher asked. ‘I’m intrigued.’

Kensy hadn’t anticipated that. The reality of being separated from the one thing that linked her to her missing parents filled her with dread.

Mrs Vanden Boom didn’t look up. ‘I promise not to lose it.’ She was completely absorbed by the device.

‘That’s a great idea, Mrs Vanden Boom,’ Max said, earning a glare from his sister. ‘We’ll come back at lunchtime, if that’s okay.’

The bell rang loudly, signifying the start of lessons.

‘Is that okay?’ Kensy repeated angrily.

Romilly glanced up. ‘What, dear?’

‘Can we come and see you at lunch?’ the girl asked.

‘Oh no, not today,’ the woman said. ‘I’ve got a meeting, then Science Club and I can’t tell you what else. Come by tomorrow before you head home, although I might need it over the weekend.’ She opened a drawer and retrieved the tiniest screwdriver Kensy had ever seen. ‘Off you go. You don’t want to be late for class, now, do you?’

Max practically had to drag his sister from the room.

‘Why did you do that?’ Kensy fumed the second they stepped into the hall outside.

‘We’ve still got mine,’ Max reasoned, trying to calm her down. ‘You said yourself it was a bonus to have two watches and that’s why we could try to get into yours.’

‘You shouldn’t have let her have it. I don’t trust her,’ Kensy said in a wobbly voice. ‘Have you forgotten what Mum and Dad said? Trust Fitz and no one else – that includes teachers! Sometimes you’re so …’ Kensy paused, as if searching for the right word. ‘Infuriating!’ She stormed towards the lockers, which were a hive of activity.

Carlos had just put his things away and closed the door when Kensy walked past. ‘Hi, how are you feeling?’ he asked the girl.

‘Fine,’ Kensy snapped, and continued walking.

Carlos frowned. ‘Was it something I said?’

Max shook his head. ‘No, something I did. Why don’t you have any books?’

‘We’re going to the Tate Gallery for a lecture this morning,’ the lad replied. ‘Can’t guarantee it’ll be very exciting, though.’

Kensy opened her locker and pulled out her Art folio. She closed the door and glanced around to see if Autumn or Harper were about.

‘Looking for your besties?’ Lola smirked. ‘They left without you.’

‘Yeah, they left without you,’ Misha parroted, hovering a centimetre behind her friend.

Kensy took a deep breath and tried to control her temper. ‘Pipe down, Lola. And seriously, Misha, you should learn to speak for yourself.’ Kensy caught sight of Carlos and her brother standing by their lockers empty-handed. ‘Where’s your stuff for Art?’ she called, still angry with her brother about the watch.

‘We’re going to the Tate Gallery,’ Max said. ‘You don’t need to bring anything.’

‘We’re meeting Mr Frizzle at the front door,’ Carlos added. ‘But make sure you pronounce it like “gazelle”, not “swizzle” – he gets annoyed otherwise.’

Kensy huffed and opened her locker, which promptly disgorged its entire contents all over the floor.

‘Do you need some help with that?’ Lola asked sweetly.

Kensy looked up at her, softening a little. ‘Really?’

‘No!’ Lola sneered. She batted her eyelashes, which looked like they belonged on a jersey cow. ‘Not my problem.’

‘Yeah, not my problem,’ Misha echoed, grinning, and the two flounced away.

‘Urgh!’ Kensy took another deep breath. ‘Seriously, could those two be any more stupid?’ she muttered, and began to pick up her detritus.

An older girl who was passing by stopped and knelt down to help. ‘Are they giving you a hard time?’ she asked, gesturing over Kensy’s shoulder at Lola and Misha.

‘It’s okay. I can handle them,’ Kensy said, jutting out her chin. ‘They’re not the meanest kids I’ve ever encountered, but they could just about be the most brainless.’

The girl laughed. She had long dark hair tied up in a ponytail and a dimple in the middle of her left cheek. ‘I’m Amelie Jagger,’ she said, handing Kensy the last of her books.

‘Kensy Grey. And … thanks,’ she said, her eyes watering.

‘Are you okay?’ Amelie asked, a crease forming on her brow.

Kensy nodded and smiled. ‘Yeah, it’s just been a bit of a rough week.’

‘You mean your parents,’ Amelie said. Not a second after the last word left her lips, the girl’s hand flew to her mouth.

Kensy frowned. ‘What about my parents?’ she whispered, taking a step towards the girl. ‘Do you know something? You do, don’t you?’

Amelie’s eyes darted around the hall. ‘No, sorry,’ she said, shaking her head and backing away. ‘I-I was thinking of someone else. A girl called Stella looks a lot like you. I, um, heard her parents were in a car accident – I was confused. Sorry. It was lovely to meet you, but I better get to class.’

Kensy watched as Amelie scurried away. She wasn’t buying it. The girl was acting as though she was expecting a hand to reach out of the ceiling and grab her. Kensy closed her locker and hurried to reception with Amelie’s words ringing in her ears. She was absolutely certain neither she nor Max had breathed a word about their missing parents to anyone.