The conflict is put into overdrive as Michael and Jimmy find common ground. Amanda proposes an unexpected partnership for mutual survival. Anthony and Nikita try to come to terms with the consequences of their actions.

The Kinsellas bury one of their own as they prepare for an all-out war against the Cunninghams, Michael and Jimmy set a plan in motion for revenge, and Amanda orders her first hit.

A Turkish cartel informs the Kinsellas that they are obliged to pay a sizeable debt owed to them by Eamon Cunningham. Viking is released from prison intent on making trouble, and a looming presence from inside the family returns.

All hell breaks loose with the unexpected arrival of a family member. While Viking welcomes him with open arms, the rest of the Kinsellas are not so pleased - most of all Amanda, whose leadership is threatened by his presence.

With Bren continuing to undermine Amanda's power, and the gardaí focusing their attention on her operations, Amanda is really feeling the pressure. And all that is before she discovers the personal and professional betrayals being conducted against her. Elsewhere, could Kem be in grave danger as under pressure from Bren, Viking pays his old friend a visit? Amanda's lawyer Lauren Bridges meets her and informs her that the guards could be closing in. And finally, Michael's trip to pick up meds from a local pharmacy proves interesting...

Viking is put in an impossible position as Bren puts his allegiances to the ultimate test this weekend. Amanda loses trust in part of the family, and the consequences begin to boil over. The Gardaí move closer to the Kinsellas, and Michael forges an intimate connection. As Frank grapples with his past and struggles with the return of Bren to the fold, things start to spiral. Nikita is cheered up by Viking with a bit of retail therapy.

Viking's allegiances are tested when the gardaí continue to question his girlfriend. Jimmy is unhappy with how Bren is going about the business. Bren seeks out Anna - very much against the wishes of Michael. Meanwhile, Birdy's past and present trauma begin to collide.

Bren's chaos reaches an apex, and the family is driven to mayhem. Michael and Viking both suffer heartbreak, while Uncle Frank seeks a change. The Batuks sew their own discord, and Amanda and Jimmy's son Anthony does the unthinkable.

The Kinsellas deal with the fallout of the Cunningham's relatiation, Frank attempts to avoid an all-out war, while Michael is torn between helping Jimmy seek his revenge and staying above the fray so he can see Anna again.

The walls close in; the Kinsellas are blacklisted by Eamon Cunningham, but necessity is the mother of invention; Amanda pitches an idea to force Cunningham back onto his heels.

The Kinsellas strike back at Eamon Cunningham as Amanda starts to blame others for Jamie's death; Michael unintentionally puts Anna in danger; the endgame starts to take shape.

Frank and Eamon deal with the stress in different ways, as Amanda continues to anger the rest of the family with her dynamism.

Frank visits his brother, Bren, in jail and remembers why his brother is not a man to be trifled with; danger lurks around every corner; Amanda and Michael come to a realization.

Eamon and Amanda meet to discuss a way to end the war; the proposal does not go over well with Frank; Jimmy and Michael meet at a crossroads; the family gathers for Jamie's memorial service.

The Kinsellas are a small but tight-knit crime family in Dublin, Ireland, increasingly at odds with a powerful drug cartel. When the hotheaded son of Frank Kinsella gets into a violent confrontation with one of Eamon's men, the Cunninghams retaliate.

Family loyalties are tested as Brent's influence seeps into each member of the Kinds clan, with Jimmy beginning to take a side as Michael's patience reaches a boiling point. Meanwhile, Viking receives unsettling news and the police gain important information.