To win the battle for Earth, what will Thomas have to lose?

In the aftermath of the Mastership arriving in Muir Woods, Thomas, Elly, and Eno have to face the heightened danger in their situation. The Martin ship on Earth can only mean the worst: their mentor Ignatius has been captured by Mars authorities and their secret mission potentially exposed. The threesome agree that they must return to rescue Ignatius and find themselves once again on a tenuous voyage through time. In the battle to keep the hope for humanity alive, Thomas will have to make hard choices. He grapples with his feelings for Elly, the truth of his past, new alliances, and new enemies… all while he fights for the world he has been so suddenly thrust into.