Jack's finally discovered the identity of the hit-and-run driver who murdered his wife and he is now prepared to risk everything to kill the man responsible: crook Ricky Hanson. Determined that Hanson should meet the same fate as his wife, Jack lies in wait in a pub car park, engine running. Sandra becomes aware of the situation. She acts fast to prevent him confronting his nemesis, but it results in a crash that jeopardises the future of the entire team. With Jack, Gerry and Brian hospitalised, Sandra's forced to accept temporary help at UCOS from the super-efficient...
Sandra's private and professional worlds become intertwined when her mother has a fall that means she needs to go into a care home and her first choice is revealed to be the scene of a suspicious death a year earlier. Jack, Gerry Standing and Brian decide to go undercover at the home.
When an armoured security van is discovered at the bottom of a lake, the team makes a link with the murder of a woman 17 years previously. The husband of the deceased, who owned the company which the van belonged to, seems to be the prime suspect but when he is provided with an alibi, Sandra decides to dive down to examine the vehicle herself and uncovers the murder weapon. However, the killer is about to strike again.
Jack and the team reopen the investigation into the undetermined death of an elderly woman, partly consumed by her hordes of cats, whose decision to leave her estate to her cats sparked a family feud. When the deceased's pets die, her money and property comes back up for grabs, leaving the detectives with no choice but to get to the bottom of her mysterious demise.
When Brian's dog finds a body on a common, it prompts two people to confess to murder. But when the body turns out to be over 600 years old, Sandra, Jack, Brian and Gerry must discover why the pair took responsibility for a crime they couldn't possibly have committed and if they are in fact the perpetrators of other killings. Elsewhere, Strickland is rather more keen for them to solve an even more tricky mystery closer to home.
The team reopen a 20-year-old case when a camera and film belonging to a photographic lab assistant murdered in 1987 are found in a Soho pub toilet. New evidence leads the detectives into the dark underside of the modelling world and to the door of a professional footballer. Meanwhile, Brian's erratic behaviour takes an alarming turn and Gerry is less than happy when his daughter Emily joins the team and looks to Sandra as a role model.
Pullman's mother has a stroke, and this event leads Sandra to start asking questions about her father, but she ends up losing her trust in the team when she discovers they have withheld information about her father from her. The revelation that he committed suicide while under investigation for corruption causes the detective to doubt all she took for granted, but she tries to set her feelings aside when she is asked to look into the death of a circus ringmaster who burned to death in his caravan, leaving only his feet behind.