After scouting the area of Oklahoma territory as a possible home for the defeated Osage tribe which are being held as prisoners by Col. Arthur's troops, Bronco reports that the area in Oklahoma is unfit for human habitation but Col. Arthur is adamant that the tribe will only move to Oklahoma or Kansas, neither of which is acceptable to Chief Crippled Bear. The Osage wish to move to Wyoming which both Bronco and Capt. Williams support.
To make matters worse, cholera strikes with Arthur's aide, Sgt. Hughes getting it while tending to a sick Osage baby, and then Col. Arthur gets it, and they are both quarantined.
After being nagged at by Bronco to escort the Osage to Wyoming and not Oklahoma or Kansas, Arthur relents and writes a new treaty indicating this, however he dies before he can sign it. The decision is left to Maj. Trask, who was sent to relieve Arthur, but Trask ignores the treaty, claiming that the colonel wasn't in his right mind when writing the treaty. He has his own agenda and Bronco tries his best to dissuade him from ignoring the new treaty.
You got two stubborn and complicated cavalry superiors, one a colonel who is automated in following orders and the other one hates injuns cause they killed his wife. Poor Bronco really nags at them to see sense. Makes for good drama and there's a nifty action sequence at the end. Quite a moving episode which is sympathetic to the Osage.