Marcella investigates when a body is discovered inside a wall, clothed in a school blazer and surrounded by soft toys. The detective soon works out that the victim is Leo Priestley, who had been abducted a few years beforehand and was a friend of her son Edward.

Dr Fairclough tells Marcella that it might be a good idea to go back to the root cause of her blackouts - Juliet's cot death. But when she tries to relive that moment at her home, the resulting stress levels put her into another fugue state. Meanhile, the team is called out when the driver of a car abandons his vehicle after a fatal collision with a cyclist and police attending the scene open the boot to discover a body surrounded by the same stuffed toys found with Leo.

Marcella digs deep in her attempts to take down Phil Dawkins, but her dogged pursuit has tragic consequences, causing her to question everything. Meanwhile, her ongoing blackouts mean she has to face up to the threat of losing her children.

Marcella needs to take control of her blackouts urgently or risk losing her children. Meanwhile, her pursuit of Phil Dawkins ends with tragic consequences.

Marcella learns the horrifying truth about the scale of the killer's crimes when she discovers the murderer's lair.

The arrest of Vince Whitman causes massive fallout between Tim and Marcella. Meanwhile, Postfeed24's internet viral video leads the team to discover another body much closer to home.

Marcella heads to Nigel Stafford's house to question him. As she walks around the house she finds a small grave before heading inside the unlocked door. Inside she's confronted by Nigel, holding a knife.

Marcella has no time to lose as the killer has Edward. Following leads she races to the killer's house, but finds it empty except for a ringing phone. However, a premonition offers up clues, but can she get to her child before it is too late?