Thorne

DI Tom Thorne, scarred both inside and out by the cases of his past investigates a serial killer who has left a fourth victim unlucky to be alive, suffering the effects of a deliberately induced stroke.

Thorne is forced to conduct his investigation alone when Tughan dismisses his "locked-in" theory. He and Anne Coburn try to help Alison Willetts communicate. A woman who claims to have escaped the killer is attacked.

Tughan identifies pathologist Phil Hendricks as his prime suspect, and seems determined to expose the dark secret that binds him to Thorne. Anne's daughter Rachel unwittingly puts herself in danger.

Two women have been murdered simultaneously near St Pancras station, but in quite different ways. When the connection is made with two other murders, months before but on the same day, DI Thorne realises that two serial killers are at work in a macabre partnership.

One of the killers is caught after a failed attempt on the life of the son of another victim. He confesses to his crimes, but refuses to identify his partner. Thorne decides to free him in an attempt to force the other killer to come forward.

Palmer escapes from police custody and he and Nicklin resume their series of murders. DS Chen, desperate to prove herself, risks everything to catch the pair.