Danny wins a chance to ride-along in an ambulance, and Rex hops in. The MD insists, "Most of our calls are routine." A car careens over a bridge, and Rex rescues a girl from the river. Rex climbs a hot apartment fire escape and drags a woman out to land in a firefighter's net. He even knocks down a wanted killer hiding in an apartment - as the MD tends a splinter in a man's hand. "See what I meant by nothing exciting ever really happening?"
Danny and Rex attend a rodeo, and Rex meets Tex, a famous movie-star horse owned by Jim Pardee. They become friends and stop a rampaging Brahma bull. Rex pines for Tex, and so does Tex. Jim sends tickets so Rex and Danny can visit a movie set. Movie outlaws kidnap Tex, but are real criminals out to rob a train in the confusion. Rex and Tex chase them, bowl them over, wrap them in rope, and save the day. It was caught on film, so Rex gets to co-star in "Four-Footed Defenders of the West"!