Short answers, pulled from the story.
"The Scouring of the Shire" is the penultimate chapter of J. R. R. Tolkien's The Lord of the Rings, in which Frodo, Sam, Merry, and Pippin return home to find the Shire under the control of ruffians led by "Sharkey," later revealed as the wizard Saruman. The hobbits rouse the Shire to rebellion, win the Battle of Bywater, and end Saruman's rule.
Sharkey is an alias used by the wizard Saruman, who has lost his magical power except for his persuasive voice. He arrives in the Shire accompanied by his servant Wormtongue and admits he deliberately damaged the Shire out of revenge.
Peter Jackson decided as early as 1998 not to include the chapter, calling it anticlimactic. He moved its key elements, the burning Shire vision and Saruman's death by Wormtongue, into other scenes, including the extended edition of The Return of the King, set at Isengard rather than the Shire.
Tolkien denied this directly in his Foreword to the Second Edition, stating the chapter had "no allegorical significance or contemporary political reference whatsoever." Critics such as Tom Shippey have argued that readers who saw parallels to postwar Britain, including shortages and bureaucratic regulation under the Attlee Labour Government, were "not wholly wrong."
Merry and Pippin lead the hobbits in ambushing the ruffians by blocking a high-hedged lane with wagons at both ends. Most of the ruffians are killed in the fighting, and Frodo takes no part in the battle himself.
Saruman tries to stab Frodo, but the knife snaps against Frodo's hidden coat of chain mail. Frodo spares him, but Saruman then reveals that Wormtongue killed Lotho Sackville-Baggins, provoking Wormtongue to cut Saruman's throat before hobbit archers shoot Wormtongue dead.