After Capt. Forsythe (Gregg Barton), the commanding officer of a cavalry troop, is killed in an attack, the new leader is Capt. Robert MacClaw (Guy Madison), a military doctor who has practically no field experience. With assistance from Sgt. Elliott (James Whitmore), MacClaw tries to lead his men to safety, using his ingenuity. But then they are ordered to guide a wagon train, containing the lovely Martha Cutting (Joan Weldon), among others, through dangerous American Indian territory.