In Episode 4, Mia discovers shocking new evidence that deepens the mystery surrounding the 15-year-old case and the recent murder, significantly impacting the investigation's course.

Brian is shown in a police cell, having been arrested for Bronty's murder. Despite his DNA being found on Bronty's body, the camera belonging to Bronty has no fingerprints, raising suspicion. Detective Pendleberry questions Brian and suspects possible cover-up involving Varity.

The episode opens with a flashback of Brian teaching young students, including Mia and Gabby, CPR on the beach, which contrasts with the present where Brian is a suspect in a murder case. This flashback highlights Brian's past role in the community and adds depth to his current predicament.

Kieran is actively involved in the investigation, asking Shawn and Ash to help clear his father's name. He also talks with Olivia about a phone she took from Bronty's room, which she refuses to hand over, fearing trouble. Kieran reminds Olivia of past protection but she denies asking him to lie for her.

Trish and Olivia bring food to Kieran's house, and Olivia admits to taking Bronty's phone but refuses to give it up, worried about getting into trouble. This phone could be key evidence, and Olivia's reluctance adds tension to the investigation.