Hawks last movie, and also the third and final part of the Rio Trio, arguably the weakest of the lot. Actually there's no doubt that it can't hold a candle to either Rio Bravo or El Dorado, but it's still a Hawks movie and a pleasant ride (nearly) all the way.
At first sight, the story has little in common with the other two movies. John Wayne is Cord McNally, a Union Army colonel who is searching, in the aftermath of the Civil War, for the two men who sold information to the other side about a shipment of gold entrusted to McNally. The betrayal led to a raid in which a young loyal officer was killed. McNally is assisted by two ex -Confederate soldiers who were involved in the raid (he holds no grudge against them because they we're only doing their job) and a young woman who has her own personal score to settle with the traitors.
It's a movie about reconciliation as well as revenge (traitors cannot be forgiven) and only when we arrive in the town of Rio Lobo, the film falls in the familiar Rio pattern. The Duke is in good form, Jennifer O'Neill runs around on high heels, lifting her skirts (but showing preciously little of her legs) and the ending is pretty violent, with some bloodspattered, gory killings. The film suffers from some tasteless jokes and lackluster performances, but there's also a viciously smiling Jack Elam (always a delight) and a funny scene with Big John going to the dentist.