A suicidal man kills several people when he causes a catastrophic train crash, and Sam struggles to cope after one of the young victims dies in his arms.

When a person is found dead in the cells, Sam becomes the main suspect, leaving Ronnie and Wes facing a race against time for them to get their hands on the real culprit.

A man is found dead in a hotel room owing his ex-wife thousands of pounds in child support. The child's grandfather is the only suspect, but is the case that easily solved?

When the body of a woman is pulled from the Thames after her car is found in suspicious circumstances, the victim's abusive ex-husband seems to be the prime suspect.

Following the suspect death of an old woman, Ronnie and Sam are lead to believe that the old woman's carer was to blame.

A gay father is found beaten to death and the son that he adopted with his partner is missing. In a race against time, Ronnie and Sam go on the hunt for the missing boy.

Ronnie and new partner Joe Hawkins, who has come from the child protection unit, investigate a gruesome double murder where the victims' hands and teeth were removed.

Philip Gardner, a psychiatrist specialising in troubled adolescents, is stabbed to death and Ronnie initially believes that one of his clients is the culprit.

When a car is pulled from a river with a skeleton in its boot the pathologist reckons both have been there for a quarter of a century and eventually the dead man is shown to be Taylor Kane, one of the first black undercover officers, who disappeared at the time of the Brixton riots.

Unemployed family man Neil Lester is battered to death with a paper-weight in his own home, having convinced his wife that he has been working for the past nine months

The body of elderly businesswoman Ranya Habib is found at a suicide spot but foul play is suspected after a neighbour tells Ronnie he heard her arguing with somebody.

Maids find blood-stained sheets but no body in a hotel room, booked with a credit card stolen from businessman Charles Hutton by Rufus Barton, a school classmate and secret lover of Hutton's daughter Georgia.

When a spate of shootings claims one of Ronnie and Joe's own, Wes Leyton, the pair are left with a race against time as the next target the shooter has in his cross-hairs is CPS boss Henry Sharpe.

Still affected by the death of one of their team, Ronnie and Joe have a new case to deal with when a young mother is stabbed to death in a busy London marketplace.