The Closed Route

is episode 231 of the Naruto: Shippūden anime.

Summary
Shikamaru begins to feel the pressure of shouldering the lives of his friends in the upcoming Fourth Shinobi World War. To help ease his mind, Shikaku sends his son along with Tenten on a mission to Mokuzu Island to replenish supplies. On the island, Shikamaru meets up with Naruto's group. Soon after they set sail, the fog around the area gets thicker and they encounter reef systems, a huge rock and a whirlpools again and again. Shikamaru figures that their ship is sailing through the bay in circles and tells Naruto and the others to sail straight for it and get swallowed up. The Mozuku on seeing the ship wrecked arrives at the spot with his gang to loot the wreckage. Having stored the ship in Tenten's scroll, they proceed to defeat the criminals.