Naruto: Volume 23
Jiraiya and Naruto finally track down Tsunade in a seedy gambling hall, and Naruto can't believe the offer Jiraiya makes her. But someone else has found Tsunade as well, with a sinister proposal of his own - Orochimaru! While Tsunade weighs her options, Naruto wears himself out working on the final stage of the Fourth Hokage's powerful jutsu. He's made a bet with Tsunade that he'll master the Rasengan, and he's only got a week to do it!
Episode 89: An Impossible Choice: The Pain Within Tsunade's Heart
Episode 90: Unforgivable! A Total Lack Of Respect!
Episode 91: Inheritance! The Necklace Of Death
Episode 92: A Dubious Offer! Tsunade's Choice!