A Shinobi of the Leaf

is episode 356 of the Naruto: Shippūden anime.

Summary
As a tied up Kinoe is led out of Orochimaru's hideout by Kakashi, one of the glass silos suddenly breaks open and a giant snake comes out of it. The snake attacks Kakashi and swallows Kinoe. Kakashi manages to save Kinoe by killing the snake, shocking the latter since Kakashi was targeted by him. The snake's carcass emits a poisonous fog, weakening Kakashi. Kinoe manages to bring Kakashi to a safe spot and saves him by administering an antidote. Unable to steal the Sharingan as per Danzō's orders due to his friendship with Kakashi, he leaves Kakashi with a note explaining his plan to deceive Danzō with a decoy wooden eyeball. Danzō is furious with Kinoe's change of heart and orders a cursed mark to placed on him. Elsewhere, Kakashi reported the incident to Hiruzen and Hiruzen sends Kakashi and Yūgao to dispatch a summon for Danzō. At the Root, Kakashi and Yūgao are stopped by the Root members, claiming that Danzō is not there. Kakashi orders Yūgao to report back to Hiruzen while Kakashi goes and saves Kinoe. On exiting the Root, Kakashi and Kinoe are cornered by the members and Danzō. Hiruzen arrives at the scene in time to save them and convinces Danzō to let Kinoe join the Anbu that is under him. Although Danzō agrees, he refuses to remove the cursed mark placed on Kinoe. The next day, Kinoe formally introduces himself to the other Anbu members, who warmly welcomes him as "Tenzō" under Kakashi's encouragement to discard his Root codename.