Four teens in a block basement launch a ridiculous banana-slide experiment that goes badly wrong when something under the floor starts talking back.
Under block 4B, the basement smelled like stale crisps, hairspray, damp concrete and whatever had once been spilled here and never forgiven. It was the kind of place where teenagers did not gather unless they were plotting something, hiding something, or both.
Kuba, self-appointed president of the Losers' Club, straightened the chairs they had rescued from the rubbish chute and tried to look like a visionary instead of a boy in a Minions sweatshirt. Behind him, the wall was covered in graffiti, most of it courtesy of his little brother, self-declared commander of the Stinky Socks. Someone had added a moustache to a faded warning sign. Someone else had written, in black marker, YES, WE KNOW THIS IS A DUMB IDEA.
Kuba ignored it.
"Right," he said, clapping his hands once. "Today we test the Professional Banana Slide. Version 2.0."
Marta stopped rolling her eyes just long enough to stare at him. "You mean the thing that made you eat stairwell dust last time?"
"That was a prototype," Kuba said. "This time we have engineering."
He slapped the side of a flattened cardboard box with a flourish. Next to it lay their new launch mat: bubble wrap, duct tape and a suspiciously sticky rug they had found near the bins. If it failed, at least it would fail loudly.
Hubert, the oldest and therefore automatically considered the most responsible, shoved a hand into a packet of crisps and spoke around a mouthful. "I hate that I’m the only one here old enough to know this is illegal in spirit."
"It’s not illegal," said Anka from behind her notebook. She was the youngest, which meant she wrote everything down as if history might one day need it. "It’s experimental."
Marta lifted a phone from a tripod assembled out of a broom, a rusty crate and the remains of an ironing board. "Experimental is what we call it when we want the internet to respect us later."
Kuba pointed at the open cellar door at the far end of the room. A narrow strip of light from the corridor cut across the floor like a challenge. "The plan is simple. I slide. Marta films. Hubert keeps the music dramatic. Anka records the results. We become legends of the estate before dinner."
"Or insurance cases," Hubert muttered.
That almost made Kuba laugh, which was dangerous because leaders were not supposed to laugh before impact.
He set the banana on top of the cardboard like a rocket on a launch pad. The fruit looked absurdly serious, as if it understood the role history was about to force on it. Marta raised the phone. Hubert tapped a beat from some terrible remix. Anka opened her notebook to a fresh page and wrote the date in large letters, as if that might improve their odds.
"Ready?" Kuba asked.
"No," said Marta.
"Obviously," said Hubert.
"Yes," said Anka, far too enthusiastically.
Kuba drew a breath. "Three. Two. One."
The cardboard shot forward.
Kuba pushed off.
For half a second, everything worked. Then the bubble wrap began to hiss.
Not pop. Hiss.
A thin silver bulge rose beneath it, as if something under the mat were breathing.
Marta dropped her phone. Hubert stopped the music mid-beat. Anka’s pen froze above the page.
The cardboard lurched sideways. The rug buckled. A strip of foil snapped loose with a sharp crack and whipped across the floor like a live wire. Somewhere beneath the concrete, something answered with a deep metallic thud.
Then a skinny shape slid out from the crack near the skirting board.
At first Kuba thought it was a cable.
Then it twitched.
A tiny hoover stood beside the boiler, the kind that belonged in a cupboard and definitely not in a basement full of teenagers. Its lights blinked once, twice, like eyes adjusting to the dark.
And in a low, flat voice that made the whole room go cold, it said, "Don't start a panic. I'm taking control of the club."