Earth destroys Mars' moon Deimos in response to the MCRN's nuking of Phoebe. This creates tensions in Bobbie Draper's squad. Holden and his crew return to Tycho Station, angry at Miller for killing the lead scientist on the Protomolecule project. Fred Johnson offers Miller safe passage off Tycho, but Miller's investigations show that action must be taken against Eros. Johnson and Holden reach the same conclusion when Amos figures out how to get one of their prisoners to talk. Miller realizes that Eros must be destroyed, and that Fred Johnson has the equipment necessary to do so.
Two hundred years in the future, in a fully colonized Solar System, detective Josephus Miller, born in the asteroid belt, is given the assignment to find a missing young woman, Julie Mao. Joining his task is James Holden, formerly first officer of an ice freighter who is involved in an incident caused by the tense relationship between Earth, Mars and the Belt. Soon the two find out that the missing woman is connected to a vast conspiracy.