A married farmer falls under the spell of a slatternly woman from the city, who tries to convince him to drown his wife.

A reluctant cavalry Captain must track a defiant tribe of migrating Cheyennes.

After Custer and the 7th Cavalry are wiped out by Indians, everyone expects the worst. Capt. Nathan Brittles is ordered out on patrol but he’s also required to take along Abby Allshard, wife of the Fort’s commanding officer, and her niece, the pretty Olivia Dandridge, who are being evacuated for their own safety. Brittles is only a few days away from retirement and Olivia has caught the eye of two of the young officers in the Company, Lt. Flint Cohill and 2nd Lt. Ross Pennell. She’s taken to wearing a yellow ribbon in her hair, a sign that she has a beau in the Cavalry, but refuses to say for whom she is wearing it.

In the waning days of WWI, a U.S. “Mystery Ship,” sets sail for the coast of Spain towing a submarine. Their mission is to find and sink a U-boat that has been especially effective in attacking Allied shipping. Posing as a harmless schooner, the mystery ship is in fact fitted with a formidable gun capable of sinking a U-boat. Stopping in the Canary Islands to refuel, the crew interacts with locals involved with Germans, and with Germans themselves, including the sister of the U-Boat commander, who is lurking offshore waiting for the coming battle.