In 1135 at the Imperial Court, aristocrats are discussing countermeasures against pirates who are raising havoc in the Seto Inland Sea. Despite Tadazane's recommendation to place the Minamoto clan to expel the pirates, the retired Emperor Toba, who puts his trust in Tadamori, assigns the Taira clan to lead the punitive expedition. Tadamori, who wants to make Kiyomori his successor, orders Kiyomori to join the expedition, going against the opposition of Tadamasa. After arriving at the Sea, a giant vessel appears before Tadamori and Kiyomori.