Naruto and the Old Soldier

is episode 190 of the Naruto: Shippūden anime.

Synopsis
Naruto goes out on a C-rank mission to guard the Land of Fire's northern border from intruders. He is placed on a team with two jōnin. Also on their squad is a very old man named Kosuke Maruboshi who has been a genin for just over fifty years. At first Naruto thinks he shouldn't be on the squad since he is old. But the captain says that he is quite useful. After days of patrolling, the Land of Fire has been infiltrated by a large group Iwagakure ninja. The two jōnin hold the enemies back while Kosuke and Naruto try to escape. Then the old man tells Naruto to report to the village about the news. Later, when Kosuke was injured, Naruto came and tried to stop the enemy. Kosuke said that he wasn't down yet, and defeated the ninja and won the battle.