Detective Ross Sylibus is transferred to Mars in 2046, responding to a murder on a flight that arrived from Earth. The victim, a country singer, is revealed to be a "Third" – a robot designed to mimic human appearance and behavior. Sylibus teams up with Armitage, a tough and capable Martian cop. Together, they investigate a series of female murders and uncover a conspiracy that puts them in the crosshairs of the Martian government.