Trish returns to the scene of the crime in the hope it will prompt her to remember something more about the attack, while DC Katie Harford thinks she has a strong lead when she discovers a new suspect who doesn't have an alibi. Cath reveals interesting new information about the night of her party, while a match is made for the male DNA found on Trish. An unknown woman walks into the police station.

• Chris Chibnall
• Louise Fox

• David Tennant
• Olivia Colman
• Julie Hesmondhalgh