In order to get the Hakawi to make more blankets O'Rourke agrees to let them borrow the fort's cannon for their Moon Festival. Agarn is against this but he eventually goes along with it. O'Rourke has all the bases covered for this deception including keeping Parmenter busy on a date with Wrangler Jane...but he doesn't count on a surprise visit by General Grant.
It's pay call at Fort Courage when a top secret letter from Washington arrives. F Troop has been chosen as a test troop for a new style of Indian fighting...infiltration through camouflage. Major Bentley-Royce of the Bengal Lancers will be instructing them. He is a master of disguise and a living legend known as 'The Phantom Major'. He also wants to prove the fort is obsolete. O'Rourke and Agarn will have to enlist the Hakawi in order to prove him wrong.
There's a $5,000 reward out for the capture of the Colton brothers and Parmenter decides to go after them. Meanwhile O'Rourke's horse and Agarn are both suffering from stomach pains. The prognosis is bad for the horse and Agarn overhears the doc and O'Rourke talking and thinks it's about him. Convinced he is dying Agarn writes a confessional letter to the Inspector General.
Renegade Indian Bald Eagle has been spotted by Fort Dodge and is believed to be heading towards Fort Courage. His reputation as wild and unpredictable precedes him and Parmenter prepares the Fort for an attack. He is crazy and attacks the fort singlehandedly. When the attack fails he is captured but he escapes and takes Parmenter with him. O'Rourke, Agarn and Jane head off in pursuit.
Jane is disgusted with the saloon and the riff-raff it attracts and insists that Parmenter close it down. Parmenter looks into it and decides she's right and embarks on a plan to clean up the town. Meanwhile gunfighter Sam Urp is in town and after several clumsy accidental meetings with Parmenter swears he will gun him down next time he sees him. O'Rourke and Agarn can't afford to lose Parmenter so they set out to save him.
O'Rourke manipulates Capt. Parmenter into suggesting an incoming railroad be routed through Fort Courtage. That way, the bar that O'Rourke secretly owns will receive a windfall. To accomplish this, the U.S. Army must persuade the nearby Indians to move. They do so -- right into Fort Courage.
Agarn gets a dear john letter from his girl Betty Lou and O'Rourke devises a scheme to keep them together. He proposes sending her a letter telling her of Agarn's bravery and the fact that single handedly he killed Geronimo. What they don't plan on is Betty Lou's father printing the letter in the newspaper and Agarn becoming a national hero. Geronimo has also read the newspaper and is intent on seeking revenge against Agarn. While all this transpires Parmenter is determined to capture a bear which has been seen near the fort.
While the men of F Troop are undergoing their annual physicals word comes that the Mexican bandit El Diablo is at large. It turns out that he and Corporal Agarn are cousins and look exactly alike. Agarn with the troop under his command set out to capture Diablo...but Diablo has taken Parmenter, Jane, O'Rourke and Dobbs prisoner.