Gunsmoke S13E01 - The Wreckers

Matt Dillon and Kitty Russell are escorting a notorious outlaw back to Dodge City to stand trial. A member of another outlaw gang sees them traveling by stagecoach and switches out cotter pins on the yoke that keeps the stage tied to the horses. The pin obligingly breaks on a mountain road, causing a spectacular crash. Kitty crawls out unscathed and checks on Matt, who's unconscious but will be okay, and the outlaw -- who's comatose and dying. When she hears the outlaw gang approach, she takes Matt's Marshal's badge off his shirt and puts it on the outlaw, then spins a deceptive web for the gang, who believes her until the outlaw awakens and uses his last breaths to tell the gang what really happened. Most of the occasional-player cast of Dodge City is on hand for Kitty's later speech asking the citizens of Dodge to ransom Matt.