When a former convict at the penitentiary where Rin Tin Can 'works' passes away, he leaves his entire fortune to the stupidest dog in the West! The inheritance includes multiple buildings in Virginia City, including most of Chinatown, which isn't to everyone's taste. Even worse, the will states that if anything should happen to Rin Tin Can, everything would then pass onto Joe Dalton. Following the inevitable escape of the four Daltons, Lucky Luke will have to protect the canine millionaire!