At 120,000 feet, on the silent edge of space, the only thing protecting atmospheric test pilot Alden Firth from the lethal "Armstrong Limit"-where human blood boils instantly-is the thin metal hull of the prototype capsule Aetherius-9. The mission was supposed to be a solitary test of endurance. But then came the metallic thud on the roof. Alden is not alone. A figure in a high-altitude pressure suit is clinging to the capsule's exterior, meticulously cutting through the main parachute cables with a plasma cutter. Hacking the saboteur's telemetry, Alden discovers a horrifying truth: his attacker is the capsule's own lead architect. The man isn't a psychopath, but a desperate soul trying to destroy the program to cover up a catastrophic, unfixable flaw that a greedy corporate board ignored. He has rigged an explosive charge to Alden's viewport, giving him minutes before the glass shatters and the vacuum rushes in. Trapped in a ticking coffin, Alden is faced with an impossible choice. To survive, he must execute a desperate, suicidal maneuver: manually severing the balloon and plunging into a terrifying, uncontrolled free-fall back to Earth. It's a gamble that will either save his life or turn him into a killer, leaving him haunted by the chilling realization that survival sometimes demands the ultimate moral sacrifice.