Killer Synth is the breaking news story, and public panic is growing. Karen is hot on Niska's tail, but are her motives for finding her more personal than professional?
Casts:
Katherine Parkinson, Gemma Chan, Emily Berrington, Lucy Carless, Colin Morgan, Theo Stevenson, Pixie Davies, Tom Goodman-Hill, Ivanno Jeremiah, Ruth Bradley, Billy Jenkins, Ukweli Roach, Dino Fetscher, Mark Bonnar, Holly Earl