U.S. Marshals Nevada Jack McKenzie and Sandy Hopkins are working undercover to capture a gang stealing horses from the Navajos, and to capture the killer of a Ranger. Nevada poses as an outlaw to get in with the gang and find the leader, while Sandy pretends to be a drunken old horse thief that has knowledge of where the Navajos have hidden their ponies.

Phoebe Titus is a tough, swaggering pioneer woman, but her ways become decidedly more feminine when she falls for California bound Peter Muncie. But Peter won't be distracted from his journey and Phoebe is left alone and plenty busy with villains Jefferson Carteret and Lazarus Ward plotting at every turn to destroy her freighting company. She has not seen the last of Peter, however.