1997. Shannon Moss is part of a clandestine division within the Naval Criminal Investigative Service. In Pennsylvania she is assigned to solve the murder of a Navy SEAL's family and locate his vanished teenage daughter. The SEAL was an astronaut aboard the spaceship U.S.S. Libra-- a ship assumed lost to the currents of Deep Time. Moss believes the SEAL's experience with time travel, and his knowledge of the future, has triggered this violence. She travels ahead in time to explore possible versions of the future, and discovers that it's not only the fate of a family that hinges on her work: hurtling toward the present is the Terminus, the terrifying and cataclysmic end of humanity itself.