According to major media reports, the finale centres on the town's annual pirate festival, where an exhibition goes up in smoke and an ancient treasure map of pirate Elias Cutler mysteriously disappears. Among the returning guest stars, Phil Daniels portrays Marvellous Harris, while Melanie Walters, known for playing Gwen West in Gavin and Stacey, plays Geraldine Desai. Graham Dickson takes on the role of Tyler Brigden, and Narinder Samra appears as Sanjeev and Dev Desai, though details of his dual role remain undisclosed.
Newcomers include Hazel Caulfield as Agnieszka and Cassandra Wilson, who makes her acting debut as DI Janet Wilson. It remains unclear who stole the map or whether Geraldine Desai is connected to the fire.