Thomas fixes a horserace, provoking the ire of local kingpin Billy Kimber. He also starts a war with gypsy family the Lees. Meanwhile, Inspector Campbell carries out a vicious raid of Small Heath in search of the stolen guns.

Thomas Shelby's war with the Lee family of gypsies escalates, and Campbell puts further pressure on him to deliver the stolen guns. Meanwhile Thomas's brother John plans to marry a former prostitute, but Thomas suspects that she's still on the game.

Thomas Shelby has to deal with an IRA chief who has come to Small Heath to avenge his cousin's death. Meanwhile Campbell gets closer to the stolen guns, and Grace has to decide whether her loyalties lie with him or with Thomas.

As Thomas Shelby prepares to oust Billy Kimber, hidden secrets are revealed and the family have to face up to the problems that have divided them. Meanwhile, Campbell, obsessed with taking down the Peaky Blinders, unleashes one last plan to destroy them.