They just wanted to know why, twenty years ago, the entire Providence crew vanished without a trace. But then the stupid dark matter engine started all on its own, and now these four twenty-somethings are en route to Proxima Centauri, unable to turn around, and being harangued by a snarky hologram that has the face and attitude of the ship’s missing captain, Billie.

Cleo has dreamt of being an astronaut all her life, and Earth is kind of a lost cause at this point, so this should be one of those blessings in disguise that people talk about. But as the ship gets deeper into space, the laws of physics start twisting, old mysteries come crawling back to life, and Cleo’s initially combative relationship with Billie turns into something deeper and more desperate than either woman was prepared for.