Two Mules for Sister Sara (1970)

Plot:

Set in Mexico, a nun called Sara is rescued from three cowboys by Hogan, who is on his way to do some reconnaissance, for a future mission to capture a French fort. The French are chasing Sara, but not for the reasons she tells Hogan, so he decides to help her in return for information about the fort defences. Inevitably the two become good friends but Sara has a secret..