Over the next seventy-two hours, the “Safe-no: August” flag spread to 847 other samples. All sperm. All marked with the same chilling instruction: Do not use in August.

Dr. Voss, it turned out, had been conducting secret experiments for a private military contractor. The goal: create a “generational sterilization weapon”—a genetically modified sperm cell that, upon fertilization, would trigger a recessive infertility gene in all male offspring. The weapon was designed to be dormant for nine months, then activate like a time bomb.

Safe.

Lena raced to the cryo-bay. On the wall, a digital clock read:

It started with a single file. Patient 7712, a young cancer survivor named Marcus Thorne, had deposited his sperm seven years ago before chemotherapy. His sample was flagged in the system with a bizarre notation: