‘What about a tie?’ Curtis said, then quickly realised that wouldn’t work. The fabric had no weight to it and the vent slats were too close together to be able to feed the garment through, even if they could manage to toss it that high.

  ‘Come on, think,’ Max muttered to himself. He reached up again and jumped for extra height. As he came back down, one foot slipped off the rail and he only just managed to stay upright.

  ‘These shoes are deadly,’ the boy moaned, thinking he needed to be barefoot to get extra traction. He was just about to kick them off when he remembered there was one piece of equipment the teachers hadn’t been able to take. Probably no one had thought of it anyway.

  ‘Shoes – that’s it,’ Max breathed. ‘Curtis, take one of your laces out – quickly!’

  The boy did as he was told, though he wasn’t sure why. No one had ever mentioned that there was anything special about his shoes, though this would be a good time to find out.

  ‘Okay, what’s the deal?’ Curtis asked.

  ‘Watch and learn,’ Max said as he spun the lace around. It rotated at lightning speed before Max flung one end towards the ceiling. The thin cord stretched almost intuitively and reached for the metal grate, latching on. With one hard yank, the panel swung down on a hinge, low enough for Max to grab hold.

  ‘Whoa!’ Curtis gasped, his eyes wide. ‘That’s handy.’

  ‘Come on!’ Max pulled himself into the ceiling, then leaned back out and offered his arm to Curtis who hopped onto the railing and reached up. Within a few seconds the boys were both inside the vent. ‘This way,’ Max urged as they commando crawled along the silver ducting.

  ‘Are you sure?’ Curtis looked behind them, but it was hard to see with only pinpricks of light getting through.

  ‘Yes,’ Max said. ‘I had a look at the blueprints for the arena last week, just in case we needed to make a quick exit for any reason. It never hurts to have a plan.’

  ‘That was lucky,’ Curtis said as he followed his friend. He didn’t imagine that the National STEM Championships were a likely terrorist target, but he was glad Max had thought otherwise.

  ‘Okay, we’re here,’ Max said.

  Curtis peered through the vent and did a double take. ‘You’re kidding, right?’ He and Max were perched high above the arena floor.

  ‘Nope, and don’t worry – those shoes have some other very cool features that are about to make this absolutely okay,’ Max said.

  ‘But everyone will see us,’ Curtis whispered as Max kicked open the grate and sat on the edge.

  The lad pointed at the video screen below them. ‘No one will notice us behind that. I promise you’ll be fine. Just land on your feet, okay?’

  ‘Do I have to activate anything?’ Curtis asked. He knew Max wouldn’t lead him astray. If he could jump from the top of the Statue of Liberty, he could manage this – although on that occasion there had been the security of a parachute.

  Down below the boys could hear the announcer.

  ‘Right, everyone’s teams are in order. No, wait. I see that Central London Free School appear to be two participants short. They’ve got about twenty seconds to make it back to the arena or unfortunately they’ll be disqualified for being unable to field a full complement – even with their reserve player,’ Riley Morton bellowed. There was a moan around the stadium and the boys could see Kensy and the others huddled together worriedly.

  The headmaster of Central London Free School, Magoo MacGregor, was seated alongside his wife Tippie in the front row of the arena, having arrived at lunchtime to watch the afternoon’s proceedings. Mrs Vanden Boom had called the school to report that the children were doing very well and might likely make it to the finals, hence Magoo’s appearance. Romilly had been surprised to see Tippie, though, given the woman’s role heading up the Pharos Inventions Team, perhaps she was keen to observe the Central London Free students’ problem-solving abilities. The children were the future of the organisation, after all. Right now, Magoo’s face was red and he was directing a look of thunder at Romilly, as if it was her fault the boys were missing.

  From his position on high, Max spied the lad from Bridgewater who had given them the bum steer. He couldn’t wait to wipe that smug look off the boy’s face.

  ‘Max, we’ve got to go!’ Curtis urged. He swallowed hard and wondered what on earth was about to happen.

  ‘I’m afraid it’s not looking good for our third team, folks. Ten seconds,’ Riley Morton boomed. ‘Nine, eight . . .’ he started a countdown, the crowd joining in with great gusto.

  ‘Where are they?’ Autumn whispered. She began to turn a circle, scanning the audience, when her eyes were drawn upwards.

  ‘Kensy!’ She grabbed the girl’s sleeve.

  ‘What?’ Her friend spun around and realised what Autumn was looking at.

  Max leapt first. Curtis gulped, then closed his eyes and shoved himself off the ledge. He muttered a prayer and was bracing for impact when something miraculous happened. Just when his feet were about to hit the ground, there was a strange feeling of energy from below. A rush of air cushioned the landing and, while Curtis stumbled momentarily and grabbed Max’s shoulder, both boys remained upright. With seconds to spare they raced across the floor, appearing from behind the giant screen to join their team.

  ‘Well, I’m afraid –’ Riley began.

  ‘No! They’re here!’ Kensy yelled. ‘They’re back. They made it in time.’

  Riley Morton looked over and realised that the girl was right.

  ‘Well, you two better have brought your A game for this last session – your team wouldn’t have been too happy with you if you hadn’t shown up,’ the man chuckled.

  Max and Curtis grinned, though Curtis could still feel his heart about to burst through his chest.

  Max clocked the Bridgewater student standing to his left, a sneer on the boy’s face. He gave the lad a grin and a slight nod of the head. ‘Good luck,’ he mouthed.

  Harper nursed the champion’s trophy in her lap as the bus wove through the narrow streets towards Central London Free School. She hadn’t stopped smiling the whole way home, despite their headmaster all but stealing the team’s glory during the presentation. Mr MacGregor had leapt from his seat and raced out onto the arena floor, intercepting the trophy from Riley Morton just as the host was about to pass it to Harper, who, as team captain, had been asked to accept it on behalf of the others. Romilly Vanden Boom had watched on in horror, shaking her head at the man, who was leaping about like a lunatic, hugging the children and punching the air. Fortunately he had calmed down after a while and slunk back to his seat – but only because he’d seen Tippie giving him the hairy eyeball.

  Following a rousing singalong of ‘We Are the Champions’, a stillness had descended over the vehicle. Competitors and spectators alike seemed overwhelmed by a contagion of yawns and eye-rubbing. Clearly, the day’s excitement had caught up with them all, though the final contest had turned out to be something of a non-event. While the boys from Bridgewater and the mixed team from Inverness had put up a fantastic fight, the concluding task played to the strengths of the Pharos trainees. The first activity had been to decode a set of instructions that saw the teams building a remote-controlled flying device with the capacity to deliver a message (which had to be written correctly in another code) from their designated workspace to an oversized bucket suspended from the stadium ceiling.

  Harper had hardly believed their luck when she opened the envelope containing the information about the task. Max decoded the instructions in no time and then Kensy, with help from Autumn and Curtis, set forth building the device. They’d had the whole challenge wrapped up in half the allotted ninety-minute timeframe, much to the disappointment of their rivals.

  Dante had heard one of the Bridgewater teachers saying that they must have had help – the man had even demanded the students be searched for phones or other devices that could have assisted them. It wasn’t the most pleasant way to end the day, but none of that mattered. The STEM team from Central London Free was off to the World Championships in Singapore. When Max and Curtis had explained to the team why they almost didn’t make it back to the arena, Carlos and Alfie had wanted to report the kid from Bridgewater to the judges, but in the end revenge was a dish best served cold. The disappointment on the lad’s face was clear. Autumn and Amelie had heard him bragging at lunchtime that Bridgewater was a shoo-in – that the other kids weren’t half as clever as his team. What was that saying about pride going before a fall?

  So Max and Curtis took great pleasure in raising the trophy and giving the boy a wink.

  Romilly Vanden Boom stood up as the bus came to a halt outside the school gates just after five o’clock.

  She and Monty Reffell had ridden back with the children, while the headmaster and Tippie had driven straight home from the event.

  On the street, parents huddled together chatting but as Harper led the team off the bus with the trophy held high, her father began a rousing cheer, which everyone joined in. Tales of their victory were soon being shared.

  ‘Who’s collecting you two?’ Romilly asked Kensy and Max. She was ticking the children’s names off a list, making sure she knew how each student was getting home, given it was after regular school hours.

  ‘We’re walking,’ Max said.

  Curtis gave a wave as he hopped into his father’s car across the street. ‘Are you sure you don’t want us to drop you off?’

  Kensy shook her head. ‘We’re fine.’

  Usually they would have all headed home together, but Curtis’s dad had organised to take him to meet his mother at the Victoria and Albert Museum to see a newly installed exhibition on the history of watches that wasn’t yet open to the public. It was one of the perks of Mrs Pepper’s job as a guide to view things before everyone else. Curtis had recently become obsessed with timepieces and could spruik all manner of facts about the devices.

  That morning at breakfast the twins had been given a run-down of their parents’ days. Their mother had late surgery scheduled, their father had a meeting with some bigwigs that was expected to run into the evening and Fitz said that he would bring takeaway for dinner on his way back from an investigation he was doing in Surrey. Max had sent them all, as well as Granny, Grandpère and Grandmère, a text message to tell them they’d won. So far only his mother’s parents had replied, saying they were absolutely delighted.

  ‘See you tomorrow, Autumn,’ Kensy called out to her friend, who was standing on the footpath holding her phone, but the girl didn’t respond.

  ‘Autumn!’ Kensy called again and still didn’t get an answer. ‘I’ll be back in a minute, Max.’

  Kensy scurried over and touched the girl’s shoulder.

  Autumn spun around, a look of surprise on her face.

  ‘Is everything all right?’ Kensy asked.

  Autumn stuffed her phone into her pocket and nodded. ‘Fine,’ she said, then smiled. ‘My aunt’s running late. I’m meeting her at Victoria Station, so I’d better go.’

  But Kensy wasn’t convinced. Autumn had been distracted for weeks now. Even today she’d almost made a mistake that could have cost them the win. Something was bothering her friend, but so far Kensy had had no luck getting beneath that cool exterior. She’d just have to keep trying.

  ‘Talk to you later?’ Kensy said.

  ‘Sure,’ Autumn said, and walked away, immediately pulling her phone back out and staring at the screen.

  ‘Something’s up with her,’ Kensy mumbled, then headed back to her brother. She’d give Autumn a call after dinner and see if she could get to the bottom of things.

  ‘Bye, Mrs Vanden Boom,’ Max said.

  Romilly ticked them off her list and bade the pair farewell.

  ‘See you tomorrow and well done, you two. I can’t believe we’ll be in Singapore in just a few days’ time, which reminds me – I’ve got a lot of paperwork to do tonight. The organisers will need to get those tickets sorted tout suite,’ the woman said. ‘I think we have a very good chance at being world champions this year.’ She smiled from ear to ear.

  The twins grinned back at her.

  ‘You know we’ll give it our best shot, Mrs Vanden Boom,’ Max said.

  ‘Oh yes, I’m counting on it,’ the woman replied.

  The twins arrived home to an empty house, exactly as they’d expected. They both got changed out of their uniforms; Max hanging his up neatly in the wardrobe while Kensy left hers where it landed on the floor.

  ‘I hope Fitz gets home soon. I could eat a horse,’ Kensy called as she thumped downstairs to the kitchen. She was also hoping there was still some chocolate cake left.

  Max followed her with a pile of books. He had a maths assignment he was keen to get started on – although now they were off to Singapore on the weekend, maybe Miss Ziegler would give them an extension.

  ‘Do you want some?’ Kensy asked, pointing at the cake under the dome.

  Max slid onto one of the stools at the island bench and nodded. ‘Yes, thanks.’

  Kensy was secretly hoping he’d say no – there wasn’t as much left as she’d thought.

  She cut the slices almost the same, wondering if Max would realise that hers was a smidge larger, and put them on two plates. Kensy pushed her brother’s towards him while she pulled a stool around to sit opposite.

  ‘Have you noticed anything weird going on with Autumn lately?’ Kensy asked as she dug her fork into the cake.

  Max looked across at her. ‘How do you mean?’

  ‘She’s been super distracted and, I don’t know – just different. As though she’s always thinking about something else and not what we’re doing. I’ve got a feeling something’s up but she says there isn’t.’

  ‘Maybe she’s missing her mum and dad more than usual,’ Max said. ‘It can’t be easy being away from them for most of the year – and it’s not as if she can just pop over to Hong Kong for the weekend.’

  Kensy licked some chocolate icing from her lip. ‘Maybe that’s it. I was out of sorts when Mum and Dad weren’t around – but then they were missing and we had no idea if they were ever coming back. At least she can talk to her parents every day, and her Aunt Cara is so lovely.’

  Max nodded absently and opened his maths book.

  ‘You could talk to her,’ Kensy said. ‘I’m sure she’d tell her future husband what’s up.’

  Max rolled his eyes. ‘As if.’

  ‘What? As if you’re not going to marry her? Of course you are. I’ve never met two people more suited. Although visiting your future house would be a scary prospect. I wouldn’t want to walk on the floor in case I left footprints on the carpet – which I’m sure you’d both vacuum every day, at least twice,’ Kensy teased.

  Max grinned. Kensy was right that he liked Autumn a lot. She was smart and funny and very pretty. But marriage – that wasn’t something he wanted to contemplate at twelve years of age. Even dating was some time off.

  ‘Imagine your pantry. Everything would match and the labels would be perfect and . . .’ Kensy was interrupted by the doorbell.

  ‘Are you going or am I?’ Max asked his sister, who was licking her finger and dabbing the cake crumbs on her plate.

  ‘You can,’ Kensy said. She’d noticed Max hadn’t eaten all of his slice and was planning to polish it off while he was gone.

  Max slipped down from the stool and walked to the screen near the kitchen doorway that showed the front porch.

  ‘It’s Mr MacGregor,’ the boy said.

  ‘What’s he doing here?’ Kensy asked, but Max had gone to the door.

  Kensy hurried over and pressed the button on the bottom of the screen to listen to their conversation.

  ‘Hello, sir, what can I do for you?’ She heard her brother ask.

  ‘Evening, Max, well done today. That was a sterling effort from Central London Free,’ the man replied.

  Kensy wrinkled her nose. She didn’t imagine Magoo had made a house call to congratulate them on their win. There had to be something else.

  ‘Could you get Kensy, please?’ he asked.

  The girl’s heart sank. She couldn’t remember doing anything lately that would warrant a personal visit from the headmaster. She was already halfway up the stairs when Max called her name – there was no point putting it off and she didn’t especially want Max inviting the man in.

  ‘Hello, Mr MacGregor.’

  ‘Hello, Kensy. I need you both to come with me,’ Magoo said.

  ‘Why?’ the girl asked with a frown.

  ‘I’ll tell you on the way,’ Magoo replied. His tone was so calm and even, as if he was deliberately trying not to worry them – but it was having completely the opposite effect.

  ‘On the way where?’ Max asked.

  ‘Please, children, we need to hurry,’ Magoo said.

  ‘What’s wrong?’ Max demanded, a sick feeling rising in his stomach.

  ‘It’s your grandmother,’ the man replied. He stepped aside to let them see the black cab idling in the street.

  Kensy looked at her brother, her eyes full of fear.

  ‘Where are Dad and Fitz?’ she asked.

  ‘Already there,’ Magoo said.

  Max felt his stomach twist. He grabbed his sister’s hand and pulled the front door shut. The twins followed Magoo to the taxi and the three of them bundled inside.

  The taxi sped through the streets before entering a nondescript mechanics’ garage. A roller door promptly slid down behind them before another garage door opened up in front. The driver accelerated through onto a hidden lift and seconds later the vehicle descended into the subterranean lair.

  Kensy leaned her head against the window, a fear she’d never known gripping every inch of her body. If what Mr MacGregor told them was true – that their grandmother had been poisoned – they might already be too late.