Railroad detective Matt Clark solves mysteries with his assistant.

Infamous outlaw Augustine Chacon murders two Texas Rangers, prompting Matt and Margaret to travel south of the border to bring him to justice.

Matt and Margaret follow the trail of Cherokee Bill after he kills a marshal riding a train, and they find the outlaw hiding out in his mother's cabin.

Cattle rustling leads to the cancellation of a contract to supply beef for railroad construction crews, and Matt Clark is called in to stop it.

Two criminals vow to fight the railroad when their homestead is threatened.