The ninja are invited to the beautiful Shintaro Kingdom to celebrate the young Princess Vania’s birthday. At first glance, the Ivory City looks like a pristine place, but the ninja soon uncover a dark, obscure, long-forgotten underworld: The Dungeons of Shintaro. Once inside, they must fight their way to freedom through a maze of tunnels paved with dangers and strange creatures ruled by the merciless Skull Sorcerer. The ninja must choose their path wisely…