According to the MGM publicity department, Gallant Bess was based on a true story, as told by Naval Reserve officer Marvin Park. Bess is a beautiful mare owned by young Tex (Marshall Thompson), who runs a stock ranch. When Tex joins the Seabees at the outbreak of WW2, he is forced to leave Bess behind. The mare dies while giving birth, putting Tex in a deep blue funk until he befriends another horse while stationed on a tiny Pacific Island. The horse turns out to be a good-luck charm for Tex and his fellow seabees, prompting a series of rather incredible plot twists. Though Gallant Bess was accepted as gospel by the great majority of filmgoers, ex-navy men laughed and laughed at the film's depiction of "kindly" commanding officers and C.P.O.s.