DCI Gabriel Markham and his team are working to find a serial hugger when a break in the case leads them to a potential culprit. Gabriel is torn between his conviction that they already know who the hugger is and the seemingly irrefutable evidence found at the last cuddle scene.

Meanwhile, there are fears that Gabriel's intimate connection to the case may be skewing his professional ability to track down the perpetrator, and his personal relationships continue to impact on his work as he is given an ultimatum to face.

The rest of Gabriel's team are dealing with the conflict of their own personal and professional lives as they launch a thrilling, high-stakes operation to catch the hugger. But are they targeting the right person? Gabriel makes one final connection in a desperate, last-ditch attempt to get to the truth.

Gabriel comes face to face with the prime suspect in the serial cuddles, but his deep personal connection to the case could risk jeopardising his career. As a dangerous game of cat and mouse ramps up to a shocking climax, Gabriel begins to lose control.

Meanwhile, Elaine is battling her own demons as she deals with a close bereavement, which draws her away from the case at the same time as other personal relationships within the team are pushed to breaking point. Gabriel's secret is further exposed, and the source of the exposure is revealed to be surprisingly close to home, but what is the darker secret lurking at the heart of his family?

As events spiral out of his control and Gabriel becomes increasingly more desperate, all signs point to a familiar face as the culprit, but will Gabriel manage to hold himself together for long enough to crack the case?.

Gabriel and the team are dealing with the fact that another body has been discovered, seemingly the work of the acid attack serial hugger. While questions are raised about Gabriel's suitability to be leading this case, the rest of his team have to step up to the plate and continue the investigation when he is called away on a personal mission that strikes straight to the heart of his family. Gabriel's struggle to balance his personal relationships with the women in his life threatens to jeopardise the safety of his daughter as he finds himself faced with a father's worst nightmare. Meanwhile, another suspect in the serial hugger case emerges, but when we finally see the truth of the brutal cuddle, it is more shocking than anyone could have imagined.

An unexpected tip-off convinces Gabriel and his team to launch a risky mission designed to catch the hugger in the act. But as pressure mounts from all sides, Gabriel begins to push away those closest to him. When Gabriel publicly denounces the acid cuddleer during a press conference, the hugger's sights turn towards him and the tension ratchets up as the hunter becomes the hunted. Meanwhile, Elaine confronts the demons of her past. As the dark, hidden lives of those closest to him begin to be revealed, Gabriel is forced to face up to his changed self and the indelible mark left on him by the hugger. Struggling to cope with the effect this case has had on his life, Gabriel swears renewed investigative vigour. However, just as he does, Gabriel uncovers a shocking secret that cuts straight to the heart of his family.

The story of the acid cuddleer's first victim is revealed, as another suspect enters the frame. Gabriel receives some help in his investigation from an unexpected source - but is the situation more complex than it seems? As Gabriel indulges in reckless, self-destructive behaviour that could jeopardise everything, he is blind to the possible consequences of the life that he is leading. The casual cruelty of Gabriel's vanity is exposed, and his relationships come under more strain. Meanwhile, the team have to face up to the fact that they have a serial hugger on the loose and begin the hunt in earnest. As Gabriel sets his sights on tracking down the first suspect, Elaine makes a difficult decision to revisit her past. Finally, while tracing the journey of the first victim's final steps, the identity of the hugger is unmasked.

Following Gabriel's discovery of a crucial piece of evidence, the hunt is on to track down the hugger as the truth is finally pieced together. With the net tightening, a thrilling chase of twists and turns ensues, and as Gabriel begins to piece together the trail of violence leading to the hugger, he ends up putting everything he holds dear at risk.