Shattered Promise

is episode 111 of the Naruto: Shippūden anime.

Synopsis
Kabuto explains that he killed Rinji, and that Orochimaru wants the Three-Tails for an upcoming war. He summons Rinji's corpse to attack Guren. Guren manages to fight back by crystallizing herself along with Rinji. The huge crystal, with Guren and Rinji inside, drops into the lake, causing Yūkimaru to believe that Guren is dead. His grief causes the Three-Tails to fly into a rage. Naruto uses his Collaboration Jutsu to assail the Three-Tails, forcing it underwater. Naruto goes to Yūkimaru, and tells him they will go home together.

Trivia

 * The upcoming war that Kabuto mentions, the war that Orochimaru wants the Three-Tails for, could possibly be a reference to the Fourth Shinobi World War