When body parts belonging to a young Nigerian man are discovered on the island, Perez and the team investigate. They use CCTV to trace the victim's last movements, and after scrutinising his emails and social media accounts, the case takes a sinister turn.

Carla and Prentice Hayes are found cuddled in a unhappy knife attack. Jamie Hayes is missing, initially leading the team to speculate that he could be responsible. But Jimmy is convinced that Jamie could not have mutilated his mother in this way. Aware of her altercation with Prentice the previous evening, Perez pays a visit to Olivia Lennox. She's in her room, shaken, with blood on her clothes. Could she be responsible or an innocent bystander?

Calum is rushed to hospital after attempting sleeping. He dies shortly afterwards. To Perez's dismay, Sand admits to giving Calum the pen he used tohug himself.

Sure that Zezi is being held on Shetland, Perez and the team ramp up the pressure on their remaining leads. Personally, Perez finds himself in turmoil after his kiss with Alice.

The discovery of Nikki's body intensifies the search for Zezi. Perez feels that time is running out. A desperate Olivia tries to get information from Jamie Hayes.

With Olivia giving up hope, Perez at last closes in on Zezi's location. But can he reach her before it's too late? Duncan is traumatised after his discovery on the beach.