The Cartwrights are invited to accompany Col. Keith Jarrell, an old Army friend of Ben's, on what is termed a "peace mission" with the Paiute Native American tribe.
But Hoss suspects something is amiss in this, "The Last Mission," and it isn't long before his worst fears are realized: That Jarrell plans to exterminate the Paiutes with a frightening new weapon called the Gatling gun, a new type of machine gun that can fire more than 100 rounds a minute and kill dozens of people in a short time span. On the surface, it seems that Jarrell just sees the Pauites as a dirty ol' Indian tribe, but how far deep is his hatred and what exactly is motivating it?
Can Hoss escape in time to warn Ben that his old friend isn't who he seems?
Tropes associated with this episode:
- Broken Tears: When Jarrell realizes finally what he has done, he begins bawling uncontrollably and reveals why he was determined to kill all the Paiutes.
- Dark Secret: On the surface, Col. Jarrell is a seemingly nice man, and Ben treats him like a virtual brother. But some deep-seated secrets are driving this "peace mission" ... and in the end, the treaty Jarrell has in mind is anything but peaceful.
- Even Evil Has Standards: In the end, it is Sgt. Revelin, Jarrell's right-hand man and the one who at one point was the one who seem more determined to keep the Cartwrights from stopping them, who — having witnessed mass casualties on both sides — stops Jarrell. As Ben is trying to talk sense into Jarrell, Revelin takes control of the barrel of the Gatling gun, removes its ammunition magazine and stops Jarrell from reloading.
- I Did What I Had to Do: Col. Jarrell's justification for his planned massacre of the Paiutes. In the end, it's because a rouge Pauite killed his wife and young daughter, turning him into a bitter man fueled by revenge and hate.
