Buttercup is kidnapped by a bizarre trio of outlaws, Vizzini (Wallace Shawn), Inigo Montoya (the superb Mandy Patinkin), and Fezzik (the late Andre the Giant). Westley returns just in time for to rescue Buttercup, and must defeat all three of her captors in order to do so. The two escape the kidnappers, only to be captured by Prince Humperdinck and the menacing Count Rugen, played by Christopher Guest. Buttercup is returned to the palace to await her wedding -- which, now that Westley is back, she no longer desires -- and Westley is taken by Count Rugen to the Pit of Despair, where he is tended to by an albino (Mel Smith).
In the ensuing action, Westley again encounters Inigo Montoya and Fezzik, as well as Miracle Max, a washed up wizard, and his wife Valerie, who are played by Billy Crystal and Carol Kane. As you might suspect, the good guys win, and the bad guys get their comeuppance.
The entire story is presented as a fairy tale being read by a grandfather (Peter Falk) to his sick grandson (Fred Savage).