Peter Jackson's Film Adaptation of The Return of the King:
The film opens with a sequence that shows how Gollum took the One Ring from his friend who had found it and ended up living under the mountain where Bilbo found him.
Gollum comes out of his reverie, awakens Frodo and Sam and tells them that they need to go. Gandalf, Aragorn, Gimli, Legolas, Théoden and Éomer ride to Isengard and find Merry and Pippin enjoying the bounty of Saruman's storerooms. Treebeard leads them to the Tower of Isengard where Gandalf speaks to Saruman. Pippin finds the Palantir amongst the debris, but Gandalf quickly takes it from him. They then return to Edoras. Gollum talks to himself and plots leading the two Hobbits to Shelob, which Sam overhears, but Frodo refuses to believe. In Edoras, Pippin takes the Palantir from Gandalf, looks into it and his mind is held by Sauron. After breaking the hold, Gandalf learns from Pippin that Sauron is about to attack Gondor. Gandalf then rides for Minas Tirith, taking Pippin.
In the High Court of Minas Tirith, Aragorn suggests that they march on the Black Gate as a diversion so that Frodo and Sam can cross the Gorgoroth Plains to Mount Doom. Aragorn calls out Sauron as Frodo and Sam reach Mt. Doom. Gollum attacks them, but Frodo gets to the Cracks of Mt. Doom as the Eagles join the battle at the Black Gate. Frodo claims the Ring for his own, but Gollum bites and his finger off and takes the Ring. He falls into the Fires of Mt. Doom with the Ring. The Ring is finally destroyed.