The crime drama series returns with the first episode of a two-part story. When a victim of a frenzied attack is found in the woods with his head caved in, initially the team wonders if it is a random attack or related to the location - where a local girl recently committed suicide. Banks, however, has a theory of his own. When the victim is identified as small time drug dealer Damon Horsley and Banks uncovers a link to local crime boss Steve Richards, he is convinced the hitherto untouchable Richards had a part in the murder.
The post mortem into the daughter of crime boss Steve Richards reveals that her death isn't a simple suicide – could someone else have been involved? And if so, who? While the violent Richards conducts his own unique brand of investigation, the focus shifts once again when the team discover that despite Kat's confession, she can't have murdered Damon Horsley. The break comes when evidence is uncovered that puts Kyle Finn, who found Horsley's body, in the spotlight, and under questioning he confesses to something truly shocking ‐ but Banks already knows he's lying, the real murderer has been hiding in plain sight all along.
Xun Li, a hard-working and devoted husband, makes a speech at a rally for Lanternlight – a charity supporting Chinese nationals like himself who fled persecution only to find themselves at risk from ruthless protection gangs in the UK. After the rally he finishes some work at his property rental business, calling wife Rachel as he walks to his car to head home – but he never makes it as a masked figure pepper-sprays him, bundles him into a car and speeds off.
The murder of Xun Li hits the team hard. This case is more complicated than they first thought, and it's not necessarily connected to the kidnapping. Given there are no indications of forced entry, all early signs point to Xun knowing his murderer. But Xun was also targeting protection gangs and so their boss, the formidable Wendy Xiao, is a prime suspect. And then there's Xun's property rental business – a disgruntled tenant may have an axe to grind.
Banks and the team begin the painful job of finding out exactly who was responsible for the incident that has affected all their lives.
Following dogged police work, they locate and close in on a suspect, only to be thwarted when it's proven there's no way they are to blame. While Chief Superintendent Anderson puts pressure on Helen to reign in Banks and close the case, Banks becomes increasingly certain that this is all down to one man – crime boss Steve Richards. Banks' obsession with nailing Richards sends him over the edge, resulting in Anderson exiling him from the station and making Helen acting DCI in his stead.
Having been thrust into a dark place from where it looks like there is no coming back, Banks' mission to solve Annie's murder is made all the harder by the fact he has been taken off the case and sent on gardening leave – but that won't stop him. While his old team struggle, Banks operates for the first time on the other side of the law, using his years of experience, wits and wisdom to secure the all-important break-through. It finally looks like Banks has done the impossible and is on the verge of bringing crime boss Steve Richards to justice when the case takes an unexpected twist, sending Banks and the team back to square one. Will Banks be able to come out on top after an explosive confrontation with Richards – he needs to try and begin to rebuild his shattered world.