In 1869, a train bound for the town of Colby, Texas, detained the murderer Cavendish (William Fichtner) who was about to be sent to the town for execution. Unexpectedly, Cavendish escaped with the help of his accomplices. Indian killer Tonto (Johnny Depp) and federal prosecutor John Reid (Amy Armie Hammer), who are also in the prisoner's trunk, survive through countless dangers, but are sent to prison by the latter. John's brother Dan (James Badge Dale), a Mounted Police officer, led his men to pursue Cavendish, but was brutally slaughtered by the other party. John, who was accompanying him, was saved again with the help of Tonto, who escaped from prison, and learned the true identity of the traitor among the Mounted Police. For this man who should have died, perhaps only wearing a mask can justice be upheld. White man and Indian, two people who had no intersection at all, embarked on the road of revenge...