Having caught one of Mr. Brother's killers, Earp looks for the three still at large, meeting an over-helpful Army lieutenant who hinders his search. One of the killers, disguised as a corporal, tricks a patrol into confronting a group of Cheyenne.
The Dry Gulch Gang ambushes Earp's Cheyenne agents, killing Mr. Brother. A vengeful Earp stalks the men and confronts one when the killer comes to Dodge City to finish the job on a severely wounded Mr. Cousin.
A Cheyenne chief named Bullhead races a pony against Milt Canyon and wins, but in a negotiation following the race, Canyon forces Bullhead into a deadly confrontation. Earp must bring the chief to trial for murder while holding off a lynch mob.
Receiving a tip on the location of the last member of the Dry Gulch Gang, Earp and Bat head to a Texas ranch to fulfil Earp's promise of bringing Mr. Brother's killers to justice.
Earp and Bat team up with the Texas Rangers to capture the remaining members of the Dry Gulch Gang who killed Mr. Brother, bringing one of the indicted members with them as bait.
