After failing to carry out his suicide mission, disgraced kamikaze pilot Koichi Shikishima returns to ravaged postwar Japan to find his parents dead and country destroyed. Having lost both his honor and his family, he must try to slowly rebuild alongside the thousands orphaned by the Tokyo air raids--including a woman named Noriko and her adopted child, whom he invites into the ramshackle remains of his home. But as these struggling survivors begin to reclaim a semblance of stability, a new and unprecedented threat appears on the horizon--a rampaging, colossal creature from the deep that their defeated nation cannot defend against. With no hope of aid from the occupying forces, can a ragtag militia of misfits band together to thwart this titanic terror?