"The Bikeriders" follows the story of a fictitious motorcycle gang called the Vandals. (The film is reportedly inspired by Danny Lyon's book of photography, per Deadline).
The main characters include Austin Butler's Benny, an especially hot-headed Vandals member; Tom Hardy's Johnny, the leader of the gang; and Jodie Comer's Kathy, who marries Benny in an effort to change him. While the Vandals start out innocently enough, they become increasingly violent over time, and things get complicated when Johnny turns to Benny in his search for a successor.