On a near-future Earth devastated by climate change, Dr. Cassandra Barlowe is right where she wants to be: working on an island of floating trash in the middle of the Pacific Ocean, as far away from Dr. Yana Gulsvig as possible. Cas's research on plastic-dissolving fungi is undervalued and underfunded, thanks to the invention of deleria, a drug that allows glimpses into different timelines. For the average user, it's a way to view lost loved ones or experience a different life, but it also offers a glimpse into worlds where humanity has solved its many global crises. Now, most science funding is dedicated to trawling these different timelines, searching for a reality with the solution to the climate devastation. But when Yana - the world's leading expert on deleria and Cassandra's ex-lover - is killed in a mysterious explosion in the hub of deleria research, taking the hope of reversing climate change with her, Cas is arrested on charges of domestic terrorism. Cas must delve through timelines to piece together what happened, while watching other versions of herself and Yana live out the life they could have had - happier, more in love. As brutal government agents close in and her addiction to deleria grows, Cas has to make a choice: live in the spiraling branches of reality, seeking closure for Yana's death until the drug shatters her mind, or live in the now, even if that means embracing her own damaged self and fighting, however hopelessly, for her own future and that of humanity.