On a remote, gas-wreathed outpost of a human colony on Jupiter, a man goes missing. The enigmatic Investigator Mossa follows his trail to Valdegeld, home to the colony’s erudite university—and Mossa’s former girlfriend, a scholar of Earth’s pre-collapse ecosystems.

Pleiti has dedicated her research and her career to aiding the larger effort towards a possible return to Earth. When Mossa unexpectedly arrives and requests Pleiti’s assistance in her latest investigation, the two of them embark on a twisting path in which the future of life on Earth is at stake—and, perhaps, their futures, together.