Things You Can't Get Back

As she and Ay escort Naruto and Killer Bee to the war, Tsunade questions her faith in Naruto. She remembers a time before she met Naruto when she crossed paths with Ay when he needed her medical talents to save a wounded subordinate. This encounter ultimately led up to Tsunade agreeing to help only if Ay could best her in an arm wrestling match. The Raikage wins using his speed to his advantage. After seeing the state of the patient, Tsunade requires that they tell her what had happened.