Twenty years after an attack perpetrated by androids takes the lives of those closest to him, Doctor Leander Dade is living a reclusive life on Earth—until the Alliance Fleet recalls him back into service aboard the first extrasolar colonization vessel, Ariadne. Unable to refuse this order, Leander returns to space and finds himself serving alongside androids, whom he has never forgiven for the attack.Tensions are high from the start, but when a mysterious accident strands Ariadne years away from aid, the ship's crew and colonists—humans and androids alike—must band together for survival. Leander is forced to work with the very enemy who nearly cost him his life, and he soon finds himself falling for the last person he expected: Mac, the ship's android chief engineer.After a mutiny splits the ship in two, Mac comes to the realization that he alone can save the ship and everyone on it, and Leander faces an impossible choice: intervene, or allow Mac to risk his life and their love for each other.
Cal Hunter is a cryo, a person who was cryogenically frozen after his death in the 22nd century. Resurrected four hundred years later, he now lives in the 26th century and works as a time traveler for the time agency on Mars.After a mission goes disastrously wrong, Cal returns to his present to find that he's seriously altered the timeline. All life on Earth and the Moon has been wiped out, leaving only a failing settlement on Mars of fewer than two thousand people. Even worse, Cal can no longer time travel due to his injuries.The only person who can fix the timeline is Renata Carr, a teenager from the 20th century. She's brought out of cryogenic suspension, and a reluctant Cal is put in charge not only of her training, but also her well-being. Meanwhile, Renata grapples with the grief of waking up in a strange century on another world while also coming of age—and falling in love with the daughter of one of Cal's friends.When disaster strikes the settlement, the timeline for humanity's demise rapidly speeds up. While Cal knows he must send Renata on a mission she isn't ready for, and which will likely kill her, he is torn between saving humanity's past, present, and future, or the girl he's come to see as a daughter.