Cassie and Sunny go in search of Hayley's family as the press begin to take an interest in the story. A detective who was involved in the original investigation offers his thoughts on why her disappearance remained unsolved, pointing out that Hayley's boyfriend was suspected of the crime but was never charged. The distance between where Hayley was last seen and where her body was found leads Cassie to form a new theory - that the killer may have travelled up from London, then returned before they could be questioned.

Can Sunny, Jess and the team bring the clues in the case together and unravel the secrets to solve it?

When a spine is dredged out of Whitney Marsh, a new case begins for Jess and Sunny’s team at Bishop Street CID. Four potential suspects soon appear, each with secrets to hide.

The Bishop Street team investigate the deceased's record, relationships, and enemies, and Jess and Sunny make contact with his widow. No one is as innocent as they first seem.

The team discover Asif, Mel, and Marty’s connections to the deceased, and bring Marty in. Secrets from the deceased's past come to light, and Jess reaches out to her sister.

With the details of the deceased's life becoming clearer and one suspect already being questioned, the Bishop Street team find suspects further afield.

Detectives Cassie and Sunny reunite as they take on a case concerning the remains of a body found locked in a suitcase in the River Lea. As the pair begin the complicated task of trying to identify the body, the stories of four people with apparent links to the victim begin to unfold. Old wounds are reopened when the detectives track down the victim's wife and son, who have been in the dark about his disappearance for 26 years. Who wanted the man dead and why?

A dismembered body is found in a scrapyard and the team believes the remains had been stored in a domestic freezer for 30 years. Meanwhile, after making the decision to retire from the police force, Cassie faces a dilemma when she learns she isn't entitled to her full pension payment unless she completes her 30 years of service.

When a severed leg is discovered in a bricked-up chimney flue the team get to work identifying the victim and cause of death. Cassie’s replacement on the force, DCI Jess James, has a rocky start as she clashes with a grieving Sunny.

The team work to identify the body found in the chimney flue as forensics reveal the cause of death. Jess and Sunny visit the victim’s mother to break the devastating news. They find the pair had a tumultuous relationship.

The victim’s turbulent past comes to light. While Sunny takes a trip to Paris and Jess drops in on an unsuspecting Lord, the pair continue to butt heads.

Sunny and Jess’s personal lives go from bad to worse while they struggle to keep focused. Meanwhile, the suspect list grows and a mother and son are put under the microscope.

Despite the trouble in their personal lives, Sunny and Jess attempt a reset as they follow the clues in the case.

Cassie and Sunny begin their interviews...

DCI Cassie Stuart begins to identify the people mentioned in the diary of Jimmy Sullivan.

The investigation into Jimmy's death continues, as Cassie and Sunny question Sir Phillip Cross.

It becomes clear to the detectives that the four men have conspired to come up with a false account of what took place the night Hayley disappeared. Jake is assigned to track down Tim Finch's ex-wife to hear her version of events - and uncovers disturbing information about Chris Lowe's past. On a personal front, Sunny is offered the opportunity to rekindle his past marriage, and Cassie worries about her father's failing memory.

Cassie and Sunny discover Walsh was chased by all four suspects on the night in question. Willets realizes Fiona's blood sample may have been deliberately lost by Liz.

Lies are uncovered, and suspects are taken into custody, but who's protecting who? Meanwhile, Jess plans a conversation with Steve.

For better or worse, Jess and Sunny finally get the truth from Asif, Marty, Mel, and Juliet. But both on and off the case, the truth leads to difficult decisions.

As the investigation in to Jimmy's death continues, Cassie and Sunny visit Father Robert Greaves hoping to identify the mysterious Jo-Jo.

When a skeleton is unearthed, a car key found near the body is the only clue to the identity of the victim.

A disturbing allegation about David opens up a second line of enquiry for the team. How much Tessa actually knew about David's life threatens to ruin her relationship with her husband and son. Marion gets into trouble at work and jeopardises her marriage by refusing to open up about her past. After having his phone stolen and information exposed, Colin is blackmailed again - and Sarah's secrets push her family to breaking point.

As the investigation into Jimmy's death continues, Sir Phillip Cross makes a difficult decision while Father Robert comes clean to his family and the police.

Further examination of David Walker's history suggests that he was a troubled man with a number of issues. Marion has a prickly chat with Cassie about her past and the investigation reveals her close relationship with an IRA activist. As the police enquiries encroach on their lives, Sara and Colin open up to their partners.