Isla, Nick, and 14-year-old Violet are a makeshift family living in a subterranean home in a planet that is no longer inhabitable. Their pursuits are normal enough: Nick scavenges the outside world, Isla feeds her thoughts into an artificial consciousness, while Violet gets visitors in the form of ghosts from multiple eras. (Isla and Nick do too, but they're slightly better at compartmentalizing and lying to themselves.)

When the world has run down and no future lies ahead, you take what you can get, and the ghosts do at least make for pleasant company. That is, if they are ghosts at all.