The Jet-Black Signal Fire

is episode 64 of the Naruto: Shippūden anime.

Synopsis
Danzo is brought in for questioning after being caught meeting with a young Rain ninja. Sora confronts Asuma, and Asuma admits to having killed Kazuma. He attacks Asuma, his arm once again assuming a demonic form. Afterward, Naruto gets injured while shielding Sora from the attacks of an unknown individual, presumably from Root. Furido then approaches Sora, telling him to kill both Asuma and the Hokage to avenge his father. Later on, Naruto catches Sora going after Tsunade. Sora retreats as Shizune and a few other ninja arrive, but Naruto pursues him. At that moment, a mysterious lightning storm strikes, cutting off power to the entire village.