I'm in Hell (オレは地獄に居る, Ore wa Jigoku ni Iru) is episode 345 of the Naruto: Shippūden anime.
Obito is tended to by two Zetsu clones, who help in his rehabilitation, while also telling him about Madara's goal and annoying Obito with potty humour. Obito recovers and gets used to his new artificial body parts. One day, Zetsu arrives with news of Obito's team-mates being in danger, surrounded by Kirigakure-nin. When Obito fails to break through the rock blocking the exist, the Guruguru offers himself as an armour for Obito. Obito draws power from the Demonic Statue of the Outer Path to break the rock. Madara tells Obito he will properly thank him in the future, and that Obito will come back to him. On his way to the battle site, Obito has a vision of Rin through his empty eye-socket. He arrives just in time to see Kakashi run his Chidori through Rin's chest. Rin's death awakens both their Mangekyō Sharingan. Kakashi passes out, and Obito proceeds to massacre the Kiri-nin. Somehow, Obito manages to draw an enormous power from within himself, using Wood Release: Cutting Technique, and while manipulating his new Mangekyō, seems almost impossible to beat. After the last Kiri ninja falls, Obito disregards an unconscious Kakashi on the ground, and tends to Rin. Deactivating his Mangekyō, Obito takes Rin to a bloody clearing, concluding that he is in hell.