Nightmare (悪夢, Akumu) is episode 54 of the Naruto: Shippūden anime and the first episode in HD (high definition).
Naruto has been having nightmares about the release of the Nine-Tails' power. Meanwhile at the library, Sai reads a book as Sakura sees him and comments to herself about him having "a human side". She invites Sai to come with her and Naruto to meet Kakashi. Before leaving he talks to Sakura and Naruto about friendship, and he, stupidly nicknames Sakura, "ugly", causing her to pummel the two. Afterward, Kakashi informs Naruto that he has special training that will make him strong quickly. They are cut off by Team 10, who have come to visit. Sai lunches with them and, trying to make friends, he angers Sakura by calling Ino "gorgeous" after concluding that women do not like to hear how they really are.