Harry is called upon to make a problem disappear after a night out goes awry for the sons of two warring crime families; as boss Richie Stevenson looks to pin blame, patriarch Conrad Harrigan gathers his clan with a plan.

Harry deals with the aftermath of the Harrigan family meeting as Jan wonders what's the final straw; Kevin scurries Eddie out of London after a threat from Richie; Maeve shows her hand to Conrad; chasing a lead, Harry makes a startling discovery.

Richie makes his move, putting the Harrigans on high alert; Conrad and Maeve lock horns over Eddie but agree on a Plan B; as Kevin prepares for all-out war, Harry kills two birds with one stone; an anonymous tip leads Fisk to the cemetery.

Harry pays a visit to Antoine at the urging of Bella; Fisk and Mukasa trade theories; suspecting a rat, Conrad comes to Jan for a favour; Kevin makes a startling confession; Richie calls a midnight meeting at the Sinful Monkey with shocking results.

Kevin and Harry assess scenarios in a search for insurance and an exit strategy; looking for a way back in, Brendan approaches Seraphina; left to their own devices, Bella and Jan commiserate; Richie makes a proposal; Maeve strikes.

In the aftermath of Plan B, Conrad twists the knife and Fisk has a realization: this is war. Maeve gives Eddie a lesson in the art of chess. Richie takes the bait. Harry goes searching for Seraphina and Brendan, who've gone rogue.