At 4:07 p.m. the sky stuttered. For one second the sunset froze, then rewound, and the same orange cloud slid back over the same rooftop twice. Milo blinked. He'd seen the seam. Then pale words scrolled up along the horizon: WORLD_07 - scheduled for deletion in 71 hours. His phone buzzed. The screen showed the exact same words.

Milo figures the words came from somewhere, so he chases them. The text was scrolling toward the old radio tower on Hartley Hill. He grabs his bike and pedals hard, the sky flickering above him every few minutes like a video stuck on a bad loop.

Halfway up the hill a girl steps out from behind a tree. She's about Milo's age, wearing a headset, and she looks annoyed. 'You're not supposed to see the seams,' she says. 'How are you seeing the seams?' She grabs his wrist. 'Come on. We don't have long.'

The girl, who says her name is Wren, pulls Milo into a shed full of glowing servers. 'I'm a backup too,' she explains. 'Worlds get deleted all the time. But if enough backups stay awake, the system has to keep the file. We just need more of us.'