The Lord of the Rings: The Return of the King

Two Hobbits, Sméagol and Déagol, are fishing when Déagol discovers the One Ring in the river. Sméagol is ensnared by the Ring, and kills his friend for it. He retreats into the Misty Mountains as the Ring twists his body and mind, until he becomes the creature Gollum.

Centuries later, during the War of the Ring, Gandalf leads Aragorn, Legolas, Gimli, and King Théoden to Isengard, where they reunite with Merry and Pippin. Gandalf retrieves the defeated Saruman's palantír. Pippin later looks into the seeing-stone, and is telepathically attacked by Sauron. Gandalf deduces that Sauron will attack Gondor's capital Minas Tirith. He rides there to warn Gondor's steward Denethor, taking Pippin with him.