Tess is a geologist who, under the cover of her historical research, seeks to edit the timeline to exert small positive influences against the efforts of “anti-travel activists.” Beth is a teenage punk on the cusp of adulthood in the early ‘90s who witnesses and helps cover up a killing, setting her own life veering onto a different course than she anticipated. Both women are activists at heart, surrounded by other women of all sorts invested in the struggle for justice, and both are inextricably linked to each other across time.

Because “Geologist” means something different in the world of The Future of Another Timeline: scientists and practitioners whose field of study surrounds the Machines, five constructs scattered across the globe that allow restricted travel through time using science so advanced as to seem like magic (depending on the time period). While the Machines are older than the human species itself, the group of men trying to destroy them—and in so doing, lock a terrible future into place—are making disturbing gains, unseen and unnoticed by anyone except Tess’s group of feminist geologists. As a final confrontation approaches, a collective of unlikely allies are all that stand against the creation of one terrible, final timeline.

The Future of Another Timeline is an absolute tour de force that wholeheartedly embraces the radical potential science fiction holds as a political genre. The novel plants its footing in the tradition of feminist sf that stretches from Joanna Russ backwards and forwards, exploring vital questions of power and resistance, what it means to be a woman, and what it means to fight. I savored it, I wept with it, I had to take rage-breaks with it. The book is a good book, in terms of craft and execution, but it’s also a fucking important book—an urgent book, a clear-seeing book, a book with ethics to argue as well as the passion to do so.

[A review, spoilers.]