The Tale of Jiraiya the Gallant Naruto: Shippûden : Season 6 Episode 21

Jiraiya realizes that the six Pains are all ninja he's met before. Putting various pieces of information together, Jiraiya figures out Pain's true identity, but Pain doesn't intend to allow Jiraiya to leave with that information alive. Elsewhere, the fated meeting between Itachi and Sasuke arrives, and Sasuke foresees Itachi's death.