The Infiltrator

is episode 217 of the Naruto: Shippūden anime.

Synopsis
After Sakura administers the antidote to Naruto, the team returns to Konohagakure with Karin in custody. First, they must turn back to the Land of Iron to retrieve the other members of Sakura's team. While heading home, the company is stopped by members of Root who demand that Sai tell them everything that has happened. Sai confirms that Danzō is dead and that they should discuss the future of Root with the new Hokage — Kakashi. Meanwhile, in Kumogakure, A and a small team head to the Lightning Daimyō's residence to inform him of the shinobi alliance and the upcoming war. Elsewhere, Black and White Zetsu regroup, revealing that Kisame has survived his fight with A and Killer B. A clone of Zetsu was decapitated in his stead, allowing Kisame to successfully infiltrate Kumogakure by hiding inside Samehada.

Trivia

 * In this episode, there are two errors:
 * Karui and Omoi are briefly shown with a Konohagakure forehead protectors.
 * The outline of Kakashi's mouth can also be seen clearly beneath the mask.