Mossa has returned to Valdegeld on a missing person’s case, for which she’ll once again need Pleiti’s insight. Seventeen students and staff members have disappeared from Valdegeld University, yet no one has noticed. The answers to this case may lie on the moon of Io --- Mossa’s home --- and the history of Jupiter’s original settlements during humanity's exodus from Earth. But Pleiti’s faith in her life’s work as a scholar of the past has grown precarious, and this new case threatens to further destabilize her dreams for humanity’s future, as well as her own.

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.