In June 2019, Detective Inspector Samuel Owusu and his forensics-team colleague Saffron Brown respond to a call from a mudlarking guide on the banks of the Thames. A young boy discovered a black plastic bag with bones inside. Saffron checks the bones and confirms that they are human, possibly belonging to a child or small adult. She also notices a hairline fracture on the skull, which suggests foul play.

About a year previously, Rachel Rimmer wakes to an early-morning phone call from a detective in Nice, France. The detective informs her that her husband, Michael Rimmer, was discovered dead in his house in Antibes that morning.

Forty-two-year-old Henry Lamb contemplates the next phase of his life. He used to live alone in his London apartment, but for the past year, his sister, Lucy, and her two young children, Marco and Stella, have been living with him. Lucy and Henry had a terrible childhood. A con man and his family moved into Henry and Lucy’s family home and deceived their parents, controlling them and taking their money. Lucy became pregnant at 13 by