Despite a tragic turn of events, Sunny and the team narrow down the suspects.

Following the discovery of seemingly incriminating items found at his house, Tim insists he bought them for his girls at a fete in Middenham. However, the team are not buying Tim's story. A new discovery leaves the team shocked and devastated, hitting Cassie particularly hard.

Having come to another dead end, Cassie and Sunny work on trying to prove a final theory into David Walker's death and catch the culprit.

James, Tim and Chris are exposed as having lied about their whereabouts on the night Hayley died. Pete reveals that he saw Eliot climbing into the holiday home through a window on New Year's Day, while leaves James struggling with the possibility that his son may have killed Hayley. Fran cracks a code in the dead girl's diary, suggesting that she met a local drug dealer on the night she disappeared.

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.

Cassie and Sunny interview two of the suspects again and get closer to the truth of what happened to Walsh. Balcombe believes she may have found the cause of death.

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 begins to investigate the Brentford house and the theory that one or more of the suspects may have been abused at the gatherings that took place there. The enquiry reveals some information that allows Colin to come to terms with a shame that he has lived with for over 25 years. Sara is forced to confront her past in order to prove her innocence. Marion pushes her family even further away.

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.

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.

Cassie and Sunny begin their interviews...

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

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.

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

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.

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

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.

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.

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?

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.

Cassie and Sunny identify four potential suspects who trained as police probationers together, and two of them are still serving officers. They have no luck finding the rest of the body and decide to go public about the discovery of Walsh's remains.

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