The Devil's Hour season two sees Lucy (Jessica Raine) and Gideon (Peter Capaldi) forming an uneasy alliance in order to prevent a recurring tragedy and hunt down an elusive monster. Lucy's double life sees her torn between family and duty as she finds herself in the crosshairs of her past-life husband, DI Ravi Dhillon (Nikesh Patel). Assisting Dhillon in his investigation is DS Sam Boyd (Saffron Hocking) who was mentored by DI Lucy Chambers in a previous life.

The Devil's Hour tells the story of Lucy who wakes up by terrifying visions every night at exactly 3:33 AM, in the middle of the so-called devil's hour between 3 AM and 4 AM. Her eight-year-old son is withdrawn and emotionless. Her mother speaks to empty chairs. Her house is haunted by the echoes of a life that isn't her own. When Lucy's name is inexplicably connected to a string of brutal murders in the area, the answers that have evaded her all these years will finally come into focus and Lucy's nightmares will draw her into a hunt for a serial killer in a world where nothing is as it seems.