In the early 1860s, Amos Norton, an unscrupulous financier, is trying to control all of the transportation modes in California. There are two established companies, the Morrison & Lidell Stagecoach Company, operated by Hank Lidell; and the new California Central Railroad, being pushed to completion by its president, Mark Benton. To bankrupt these two companies, Norton hires a notorious outlaw, Black Bart, to raid both outfits, making it look like each company was responsible for raids on the other. Lidell is convinced that Benton is trying to ruin him and declares open war. To stir the agitation more, Black Bart, posing as Jim Trevor, a rancher, joins the Morrison & Lidell forces. Jeff Connor, a stagecoach driver for Lidell, meets Benton and is convinced he is a square-shooter. When he openly says so, Lidell fires him and his pal, "Gabby" Chapman. Jo Morrison is in love with Jeff and her kid-brother, Chick, regards him as a hero. But when Jeff and Gabby go to work for Benton, they turn against him. But Jeff has his suspicions about who is causing the trouble, and he and "Gabby" follow Trevor one night and see him and his gang rob one of Benton's trains of its gold shipment. But before they can pursue the robbers, they run into a posse and Benton thinks they are the culprits and has them jailed.