The lab was calm. Things had started to settle, everything was becoming still. Tim blinked awake and touched a tender lump on his head. Still dazed, he watched Stephen crawl out from his hiding place. Everything was a blur – it all played out like a fever dream.

There was a distant banging, but Tim was still too dizzy to process it.

The destruction was extreme. The imagination box was in pieces and piles of rubble sat on the floor beneath tall holes in the walls. Sunlight beamed in. It was a surreal thing to see. The laboratory seemed like a ruin from an ancient civilisation – completely transformed in the short attack.

Tim watched Whitelock limp out of one of the new openings, off into the garden. He didn’t look back.

The thumping continued and Tim heard a faint voice.

To his right, at the other end of the lab, he saw Clarice locked inside the teleporter. She was hitting her fists on the inside of the window, yelling at the top of her voice. It sounded as though she was under water.

Stephen looked up through the bright light, suspended, almost solid in the cloudy air.

‘Let me out!’ Clarice shouted, softened inside the teleportation chamber. ‘Open this up, Stephen. Open it!’

He strolled towards his mother and gently grabbed the handle.

‘Quickly,’ she said.

But, with a deliberate tug, he snapped it off, locking her inside.

‘Stephen? Stephen. Open this up now. You ungrateful little tick. You will open it.’ She pushed her hands against the glass, exposing her teeth. ‘I know you will.’

Casually, purposefully, Stephen picked up the controls. He placed his thumb on the button.

‘Stephen Crowfield,’ she screamed. ‘You are a disgraceful, ghastly, repugnant lump of—’

He flicked the switch. Light flashed from the teleporter. Clarice fizzled and dissolved in an instant. Teleported to nowhere. Deconstructed but not reconstructed. Every atom, every particle that made her was now separated.

Clarice Crowfield was gone.

Stephen showed no remorse. Rather, his shoulders fell backwards and his chin tilted up. Smiling, he turned and clambered out through the wall. He landed on the lawn, and escaped towards the trees at the back of the house.

Now alone, Tim wondered whether Stephen had been waiting his whole life for such an opportunity. Would he have done it if he’d known he was being watched? There was no way to be sure.

After he’d cleared the debris from his legs, Tim scrambled to his feet and made it outside. When there was no sign of Eisenstone, Dee or Phil, he went back in through the front door, finding them in the study.

‘Tim!’ Dee yelled. ‘You made it out. It’s in there, in the passage to the lab.’

Phil dived from her shoulder and slid straight down into his shirt pocket. Tim quickly explained what he’d seen, but there was no time to discuss it. The secret bookcase was shut – Eisenstone had tipped a tall, wooden clock on its side and rammed it against the door.

‘We need to keep it contained,’ he said over his shoulder. ‘Indeed, you two grab the desk – we need to trap it.’

‘What’s going on?’ a voice asked. They all whipped around to see Inspector Kane.

Eisenstone grabbed Tim’s arm and shuffled him round behind himself, then did the same with his granddaughter.

‘Yes, yes, what do you want?’ he asked.

Kane held his hands up. ‘No, I’m … I’m sorry. I changed my mind. I don’t want the money. It was wrong. I came back to rescue you.’

The professor squinted, unsure whether to trust him or not.

‘We don’t need your help,’ Tim said.

‘Yeah, jog on, Kane, you’re not our friend,’ Dee added.

‘Look, it doesn’t matter now, listen, listen, listen, we’ve got to get out of here,’ Eisenstone said. ‘There’s a … it’s a … a monster, indeed, yes, in there. We’ve got to go.’

‘A monster?’ Kane laughed. ‘Sorry?’

He curiously approached the secret entrance.

‘No, no, no. Really, stay back. Seriously,’ Eisenstone said.

The case vibrated, books rattled off the shelves. Below, the floor rumbled and above the chandelier clinked and wobbled. Kane took a few steps back.

Before he could say another word the cabinets exploded into a thousand pieces. The beast appeared. Eisenstone, Tim and Dee went for the door as fast as they could. Looking back, Tim saw Kane hold his ground.

‘Stop, police!’ he shouted.

With a husky grunt, it tilted its head, as though contemplating the order. But then it snatched Kane by the legs, swung him round and threw him the full length of the room. He crashed straight through the window, disappearing from sight.

‘Oh deary me,’ Phil whispered.

Behind them the creature began taking the study to pieces, like a toddler flinging toys in a tantrum. It made short work of the broad antique desk, rolling it over, sliding it across the floor and then catapulting it over its shoulder. It ran its claws across the wooden shelves, turning them to wreckage with ease.

Everything it could see, it destroyed.

Tim, Eisenstone and Dee all made it through the front door and outside. They stopped on the drive and turned back to the building as a desperate roar made birds flee from nearby trees.

‘What now?’ Tim said, catching his breath.

‘Right, indeed, it mustn’t get out,’ Eisenstone replied. ‘So long as it stays in there, we should be quite fine.’

The side of the house gave way. It burst through and thudded on to the grass – a torrent of dusty debris and glass followed it.

Clarice’s prized portrait landed on the ground amid it all. Her proudest moment, beautifully immortalised in the painting. The eyes looked towards the sky, at the mercy of the surrounding destruction. A moment later, the monster’s heavy foot slammed down on top of the picture and twisted purposefully into the mud, crushing it like a finished cigarette.

It turned around and lumbered towards them.

‘Back into the house!’ Eisenstone yelled. He was right, there was no way they could outrun it on flat ground.

They made it inside, grabbing the door as its face smashed against the wood on the other side, dislodging the grand stone wall. The professor used his back and tried to push the door closed – Dee and Tim too put their weight into it. Snarling breath blasted through the gap and after a struggle the deadbolt clacked shut.

It sounded as though it had retreated.

‘It’s getting a run-up,’ Dee shouted. They all sprinted towards the kitchen. Close behind, it broke in, destroying the doorway, the stairwell and everything it passed through.

They only just made it to the back door in time, charging outside once more. The monster came into the kitchen, twirling and obliterating. The building was collapsing behind it. Tonnes and tonnes of rubble fell, pinning the creature’s lower half. It writhed and cried, flinging bricks, pots and pans with every struggle. Its mouth stretched out and tore through the cooker. The pipe split. Gas spewed out, filling the kitchen, making the air wobble like transparent jelly.

The storey above had almost entirely collapsed, turning the ground floor into a kind of pit. Walls stood with a hollow space in the middle, where the creature had trapped itself – upstairs furniture sliding, falling, smashing.

Crowfield House was in ruins.

On the grass at the back, Tim had an idea – he neatened his hat and closed his eyes. A few moments later, he opened the imagination box on the lawn, to reveal a small orange distress flare. Someone would need to light it and throw it into the gas.

Without saying a word, Phil clambered out of his pocket. He took it under his arm and headed back towards the building. Everyone else moved further away.

They watched the monkey scurry up the twisted trellis and climb over the split walls to the tilting roof. From there he could see through all the floors, down to the kitchen. The demon was still struggling wildly, but with every movement Crowfield House tightened its grip.

Phil held the flare upright; it was twice as big as him. With both of his hands he tugged the tag to light it, teetering on a floorboard from the loft that jutted out at a strange angle. Below, the creature threw concrete off its back and stumbled into a space, shouldering against the wall, stirring the gas. It was almost entirely free when Phil finally fired up the flare. It fizzed and sparkled hot, painting him red. From the ground Tim watched the bright glow appear on the corner of the house.

One final, defiant roar.

‘Toodles,’ Phil said as he dropped it.

As it fell he leapt outwards, towards the grass. Tim watched the flare and the monkey descend in different directions, almost in a perfect reflection of each other. Before Phil hit the ground the stick made its way into the heart of the gas leak. It clattered off a shard of tile and landed.

Fire, light and heat burst out, all struggling to escape the quickest. The explosion was immense. The shock wave hit them like the front of a hurricane – they shielded their faces as the mushroom cloud rose, curving in on itself.

Tim’s eyes scanned the grass, desperate to see Phil. Pieces rained down, but the monkey was nowhere to be seen.

‘Phil?’ he said, stepping towards the burning ruins, the dust now all around them.

Eisenstone grabbed his shoulder, holding him back. ‘Don’t go any closer.’

‘Phil!’ Tim yelled. ‘Where is he?’

Dee covered her mouth, looking on. The professor too seemed worried as seconds passed and the monkey still didn’t emerge.

The sound of sirens drew nearer. At the front of the house, through the broken gate, a fire engine and three police cars arrived. Their lights flickered blue but their noise grew silent as Tim stared at what was left of Crowfield House.

The building buckled and collapsed further as flames spiralled. A thick mass of black smoke flowed up, speckled and glowing, leaving a long shadow over the gardens. On top of the hill, it would be seen from miles away, filling the sky.

Tim sat on the ground and his chin began to tremble. Phil was in there somewhere. Warm tears fell from his cheeks.

Blinking, Tim thought he saw a shape on the grass. It moved, and moved some more. Then a tiny monkey emerged, limping towards them. Tim stood, ran and skidded on his knees. His fur was blackened and his paw injured, but he was alive.

‘Phil!’ Tim shouted as he picked him up.

Dee and Eisenstone stood over them. ‘Oh yes, yes, well done little monkey,’ the professor said, crouching, the fire reflecting in his glasses.

‘What a strange day,’ Dee said.

‘Indeed.’

‘That monster tried to kill Clarice,’ Tim said. ‘Her own creation, the first thing she made, wanted to destroy her.’ They stood and watched the burning wreckage for a moment.

‘I wonder,’ the monkey added, ‘what a psychiatrist would say about that?’