Rex, a wild stallion, and Rinty, a police dog, are pals. Their master , John Sheldon, is framed for murder, and Alice Ingram plans to race Rex for money to pay for John's legal defense. Meantime, Frank Nolan, who has falsely accused John, sets out to steal Rex for himself.
Rex
as Rex King of the Wild Horses
Rin-Tin-Tin Jr.
as Rinty
Bob Custer
as John Sheldon
Lucile Browne
as Alice Ingram
Ben Turpin
as Henry
Edmund Cobb
as Henchman Jim Luger
Richard Cramer
as Frank Nolan
Lafe McKee
as Charles Ingram [Chs. 1, 3, 12]
Ernie Adams
as Henchman Raymond
Slim Whitaker
as Henchman Mack
Richard Alexander
as Lewis R. Lou Salters [Ch. 1]
Jack Rockwell
as Sheriff [Chs. 1, 7-8, 11-12]
