Luffy's Fall! The Unexplored Region - Grand Adventure in the Ocean's Navel

An enormous hole opens in the ocean, and at the bottom of it sits an island called the Ocean's Navel, said to hold a treasure that can grant any wish. Monkey D. Luffy (Mayumi Tanaka) steers the Straw Hat Pirates down toward it, with Roronoa Zoro (Kazuya Nakai) and Nami (Akemi Okamura) aboard. Yukio Kaizawa sends them in as friends who will follow Luffy anywhere, though the islanders have plans of their own for the visitors.