Hundreds of years ago, a meteor struck Korea and spread a microbe that devastated human life and warped living DNA. As people rushed into the orbiting city of Destiny, some of the microbes infiltrated the new community. People separated out into the Drops, the lowest part of the city prone to microbes, and the city proper, safe from the deadly microbes. Travel between the two is strictly prohibited in order to protect Destiny, but a few people slip through.

Although the microbes kill most people they infect, some humans are able to adapt and are known as Sagents, or sex agents, recruited by government and private agencies and forced into lives of espionage and seduction. The microbes give them strength, intelligence, and extended lifespans, and their agencies take advantage of those traits ruthlessly.

Gabriel is a sagent just starting his career, already scarred by his previous agency. When he accepts a dangerous mission to the Drops, everything starts to fall apart. Isolated from his agency and not knowing where to go, Gabriel must choose between returning to safety and Destiny, or staying and forging his own path.