Sesongpremiere. Tommy har ingen kontakt med familien og bruker all sin energi på forretningsvirksomheten. Så får han et mystisk brev, der det står klart og tydelig at Shelby-gjengen risikerer å bli tilintetgjort.

Mens Shelby-gjengen bearbeider en sjokkerende hendelse, tar Tommy en beslutning han kan komme til å angre på. Samtidig kommer en ny fiende med et modig utspill.

Changretta oppdager en svakhet i Shelbys forsvar, og tradisjonene tærer på Arthur. Man mistenker at det er en forræder i Peaky Blinders' innerste krets.

The Peaky Blinders are lured by the Italians into a cat-and-mouse chase on the streets of Birmingham. As his factory lies idle, Tommy confronts the possibility that the Communists might win and he will be deemed a traitor to his class.

Tommy finds himself engaged in bloody battle with Luca Changretta and his gang. Lizzie has even greater news to break. Meanwhile, an army colonel has questions for Ada about her past as a communist, and Jessie Eden confirms just how far she is prepared to go in pursuit of her cause.

It is the night of the big fight - Bonnie Gold versus Goliath. But as the bell rings and the crowd goes wild, dangers lurk in the shadows for Tommy Shelby and his family. When Changretta plays his final ace, he sets in motion a series of events that will change the Peaky Blinders forever.