Osyraa attacks Book's home planet and the Discovery travels there to help. Stamets and Adira investigate The Burn.

After months spent reconnecting the Federation with distant worlds, Captain Michael Burnham and the crew of the U.S.S. Discovery are sent to assist a damaged space station – a seemingly routine mission that reveals the existence of a terrifying new threat.

Burnham and Tilly hunt the killer of a Starfleet officer as Stamets and the science team race against the clock to prevent the anomaly from killing anyone else.