Now that intellect and muscle have joined forces, the next phase of Senkuu's scheme to solve the enigma of the green flash that once froze humanity is to travel across the globe and trace its source. Yet, to do so, Senkuu must first construct a vessel to sail through the vast, uncharted seas.
Assisted by Tsukasa Shishiou's former henchmen, the hull of the ship is swiftly erected, but a single element remains: an experienced helmsman. While hunting for one, Senkuu and his band encounter a frozen Ryuusui Nanami—the scion of the largest shipping empire, famed for his encyclopedic knowledge of boats yet notorious for a disagreeable demeanor. Despite this, Senkuu gambles and revives Ryuusui.
Ryuusui, realizing that property claims vanish in this new society, is thrilled by the chance to seize everything for himself. But before he consents to steer their forthcoming expedition and navigate the turbulent seas, he and Senkuu must locate the monarch of fuel to power their craft—oil across the boundless, uncharted waters and face unknown dangers.
