When movie director Larry Trimble travels to Berlin searching for his next big star--a dog!--he finds Etzel, a fierce, highly trained three-year-old German shepherd police dog. Larry sees past the snarls and growls and brings Etzel back to Hollywood, where he is renamed Strongheart. Along with screenwriter Jane Murfin, Larry grooms his protégé to be a star of the silver screen--and he succeeds, starting with Strongheart's first film, The Love Master, which is released in 1921. Strongheart is soon joined by a leading lady, a German shepherd named Lady Julie, and becomes a sensation.