Helen is determined to try and win back Banks's approval as they attempt to discover the true identity of student Josh's murderer and stop his father from seeking a revenge of his own.

When the body of student Josh Tate is found dumped in a ravine, the investigation into his stabbing uncovers a very different man to the quiet character described by his flatmate Spencer. It emerges that Josh was infatuated with Spencer's girlfriend and had been manufacturing Ecstasy for club owner Liam Fallon. Meanwhile, DI Morton's ex-lover Martin Hexton has arrived, claiming to be working on a local case. When Fallon comes under suspicion as Josh's murderer the detectives break into his flat and find him badly beaten - and to complicate matters, it looks as if Hexton is responsible.

Geoff has become a marked man and Banks decides to put both him and his daughter Evie under watch at an anonymous hotel whilst he increases the search for Mullen.

A husband and daughter find it hard to deal with their grief after the body of wife and mother Anaan Kamel is discovered washed up by an underground river. Marcus Leyton, a former employee of Anaan and Raheel's law chambers becomes the main suspect.

The officers are dismayed to learn the arson attack on the Osgoods' house has injured Michael and killed his son Robbie, and local bully Gary McCready is soon questioned. As the investigation into Katrin's murder continues, the body of an older man who died of natural causes is found buried near her grave, and when Banks suspects Jason McCready abducted missing Annika, he uncovers a shocking secret. Meanwhile, the detective gives a moving speech at his mother's funeral, and the ceremony brings him closer to his father.

After the unidentified body of a woman is found on some waste ground, the team find themselves becoming involved in the world of vice in a town where nobody is happy to talk. Banks also has to deal with a personal tragedy.