Plagued by constant bandit attacks, Wells Fargo is falling on hard times. To restore public trust in their services, the company sends one well-publicised stagecoach from Denver to San Francisco. It will have the best whip as driver, a motley crew of daring passengers, and—to escort them and a precious cargo of gold—none other than Lucky Luke.

A wise precaution, because every desperado in the country will be waiting on the coach's planned route.