The series begins with the discovery of human remains on Whitney Marsh. Jess and Sunny are immediately called to the scene, abandoning their evening plans to their husband's chagrin. Dr. Balcombe's analysis reveals that the remains are relatively recent and suggest a grim conclusion: the body was placed there already dismembered. With this insight, Jess and Sunny intensify their search for other body parts.
As the investigation unfolds, viewers are introduced to a diverse new cast of characters: Melinda Ricci, an outspoken television commentator based in Ireland; Martin 'Marty' Baines, an autistic man living with his mother Dot in Deal, Kent; Asif Syed, an Afghan training for his UK citizenship test; and Juliet Cooper, a history lecturer and faculty head at a London university. While these characters live seemingly separate lives, they are intricately connected by their pasts. It's up to Jess, Sunny, and their dedicated team to uncover these hidden links and ultimately expose the truth behind the cold case murder.