A gang of evil ninjas has stolen the sacred sword of the Lady Mayu and are demanding that her family exchange her for the family treasure. The world's greatest swordsman, Shuranosuke Sakaki, is called in to get the sword back.

Having been demoted for failing to prevent the murder of one of his superiors, Mondo is startled by a group of masked thugs who are soon attacked in turn by an unseen force. He begins to suspect the work of assassins, but whose side are they on?

The spirit of Princess Lena, the last emperor of the planet Lectorius who vanished 700 years ago, arrived on Earth as a sphere of light, seeking to inhabit the body of Tsushima Reina. Reina finds herself torn between her lover Kensuke and her stepmother Miyako and her fiancé Domoto. Manipulated by the threads of fate, as the bewildered Reina wanders, she is suddenly attacked by a strange clan. What is Reina's true identity? What are her real intentions? And will the day of the Great Giant God's revival, foretold by Princess Lena, truly come? Earth's final day draws ever closer...