The map was folded inside his father's service pistol case, wrapped in oilcloth the way you'd wrap a sandwich for a long hike. Johnny found it three days after the Disappearance, when he was trying to figure out why the gun had no serial number and why his father's drawer was locked from the inside.

The map marked seven points across Chicago. Each point had a number and a word: FOOD, MEDS, KEYS, DATA, POWER, TRUTH, HOME.

Johnny was sixteen years old, five foot nine, and had spent most of his life learning how to survive on the south side of Chicago. He knew which alleys were safe, which bodegas would sell you beer without ID, and how to pick a lock with a paperclip. But he did not know what to do with a map that led to seven locations across a city that had suddenly, inexplicably, lost every adult over the age of twenty-five.

He started with Point One: FOOD. It was in a warehouse in Pilsen, the kind of warehouse that used to store produce for the city's restaurants. The lock had been cut—professionally, with bolt cutters, not forced. Inside: three pallets of canned goods, twenty cases of dried beans, and a note in handwriting that was neither his father's nor anyone he recognized: "For whoever's left. Use wisely."

Point Two: MEDS. A pharmacy in Lincoln Park, the back room behind the counter that had been broken into but nothing was missing except what was in the locked cabinet. Prescription antibiotics, insulin, painkillers. A note: "These expire in eighteen months. Use them before they don't work."

Point Three through Six followed a similar pattern. KEYS was a box of master keys for city buildings—schools, community centers, the public library. DATA was a USB drive containing the contents of Chicago Public Schools' server, plus something else: a video file, five minutes long, of a woman speaking directly to the camera. She was probably in her fifties, with gray hair and glasses and the tired eyes of someone who had been awake too long for too many nights.

"My name is Dr. Helena Voss," she said. "If you're watching this, then Prometheus has leaked. I'm sorry. I tried to contain it. I tried to reverse it. I failed. What I'm about to tell you is classified, but classification doesn't matter anymore, so I'm going to tell you anyway. Project Prometheus was designed to create a pathogen that targets telomerase-active cells—essentially, cells that divide rapidly. In theory, it would eliminate enemy labor forces without killing combatants. In practice, it eliminated everyone over twenty-five. I built a reversal, but I need seven components scattered across the city. I've left them at the seven points on the map. If someone finds them, if someone assembles them, the reversal might work. It might not. I'm sorry. I'm so sorry."

The video ended. Johnny sat in his father's apartment for a long time, listening to the sound of Chicago—sirens, shouting, the occasional gunshot, but also laughter. Kids were laughing. Kids were playing. Kids were alive.

He spent the next three weeks assembling the components. Point Seven: HOME. It was in his father's apartment. A genetic sequencer, still boxed, with a note: "For DNA analysis. You'll need this for the final step."

The final step required a genetic key—a specific sequence that existed only in people whose cells had begun the aging process but hadn't completed it. People who were twenty-five years and eleven months old. People who were... almost gone.

Johnny's father was twenty-five years and ten months old when the Disappearance happened. He was still here. Still alive. In a coma at Chicago General, kept alive by the hospital's backup systems.

Johnny stood in front of the activation panel in the hospital's basement, his hand on the button. He thought about his father—cop, husband, father, man who had taught him how to shoot a gun and how to tie a tie and how to tell the difference between a threat and a nightmare.

He pressed the button.

The lights went out. When they came back on, one light in the building was still on. In a dark room on the third floor, a monitor blinked green. And on a bed, a man's eyes opened.

That's all Johnny knew. That's all anyone knew. The rest was up to them.