With Lee in custody, evidence builds against Mia, but she still evades police efforts to find her. Cadi rushes to the hospital when she hears that Connor is in intensive care after the incident at the lake.

As Cadi delves deeper into Mia's relationship with a boy who killed himself years ago, Mia and Connor reel from what happened at the gas station. Later, Cadi is called to the scene when another body is discovered.

The community gathers together at a local church for a memorial service for Geraint. Cadi and Owen attend in the hope of securing new leads. Connor's overwhelming guilt reaches a breaking point.

After arresting Polish migrant worker Piotr Korecki, Cadi and Owen interrogate him about the CCTV footage showing his altercation with Ifan. The following morning, Sin's ex-girlfriend Hannah visits him and frets over the state of the brothers and their home. Cadi and her sisters gather to say goodbye to their family home on the island, and later, Rachel devastates Cadi by breaking up with her.

A search of the Thomas home yields a clue to the brothers' whereabouts. After tracking them down, Cadi finds Sin in dire straits-can she prevent him from doing something desperate? With the case solved, Cadi begins to pack up her desk but realizes she can't leave Wales behind without taking one last chance.

When Father McEwan's body is discovered, Rachel, in her capacity as pathologist, tells Cadi she thinks the murders are linked-but she doesn't want to engage with Cadi beyond the professional. The detectives question Dafydd, who reveals his suspicions about Ifan's long-ago involvement in the arson attack that killed Branwen Thomas. Cadi sends a team to the Thomas house, but the brothers have fled.

Cadi argues with her sister about their ailing father. Later, Lowri recounts the details of her attack to the police, leading them to question her abusive ex-boyfriend, Marc.

With Megan and Nia safe, the police search Dylan's house, but he has disappeared. Cadi interviews Iona, hoping to get information about the abducted girls and capture Dylan at last.

Dylan releases Megan from her shackles but threatens to chain her again if she tries to run away. Cadi questions a man in prison who was convicted for the murder of another young girl, a crime that Cadi believes may be linked to Mali's death.

DI Cadi John investigates the death of a young woman found in a river, who appears to have been shackled for some time before her demise. Cadi and her colleague DS Owen Vaughan identify the body as Mali Pryce, a troubled girl who disappeared years ago.