When Jack and Nikki enter a high-security prison to investigate the suspicious death of an inmate, the case brings up disturbing memories for Nikki.
The victim’s cellmate is Scott Weston, the student responsible for a mass shooting she witnessed ten years earlier. Nikki becomes increasingly convinced that Scott is their prime suspect, but Jack worries she is not following the evidence.
After a surprising breakthrough in Jay’s case, Nikki struggles to accept that Scott may not be responsible. Meanwhile, DI Mason asks Jack and Nikki to investigate the death of someone close to the case.
What at first appears to be a house fire, Jack confirms was an arson attack, and Nikki discovers that the victim was murdered before the fire was set. The team struggle to find a connection to Jay’s case, but when crucial evidence is retrieved from the scene, their attention returns to the prison.
Silent Witness returns Monday 6th September at 9pm on BBC One.