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.

Important pieces of evidence come to light against all the key suspects in the case – Ellie and Hardy can feel the vice tightening and know that soon, the case will crack open...