The central twist of For a Few Dollars More is the revelation of Colonel Mortimer's true motivation for hunting El Indio. For most of the film, he appears to be a rival bounty hunter, competing with Manco for the same prize money. The truth is revealed in the film's climax: the beautiful woman in the photograph inside El Indio's musical pocket watch is Colonel Mortimer's sister. Years ago, Indio murdered her husband and raped her, which led her to take her own life during the assault. El Indio is haunted by this memory, which is triggered by the watch's chime, while Mortimer carries an identical watch, a memento that fuels his cold, calculating quest for revenge.
This revelation re-contextualizes the entire film. Mortimer's professionalism, his specialized weapons, and his intense focus are not for money but for a deeply personal vendetta. The final duel is not about a bounty; it is a ritual of justice. Indio challenges Mortimer to a duel where Mortimer is disarmed, but Manco, having figured out the connection, intervenes. He gives Mortimer his gun belt and produces the second watch, starting its chime and telling them, "Now we start." This makes the duel a fair fight. Mortimer kills Indio, looks down at the watch in the dead man's hand containing his sister's photo, and achieves his life's purpose. He then tells Manco, "The reward is all yours," and rides away, having no interest in the money. Manco, after a moment of reflection, proceeds to load all the bodies, including Indio's, onto a wagon to collect every single bounty, reinforcing his pragmatic nature while also having served as an instrument of justice.