Birmingham, 1919. Thomas Shelby controls the Peaky Blinders, one of the city's most feared criminal organisations, but his ambitions go beyond running the streets. When a crate of guns goes missing, Thomas recognises an opportunity to move up in the world.

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.

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.