In this sequel to Umiazaru, we find protagonist, Daisuke Senzaki (Hideaki Ito), having matured considerably as a search-and-rescue diver for the Japanese Coast Guard. Blessed with great camaraderie among his colleagues, particularly his friend and diving partner, Tetsuya Yoshioka (Ryuta Sato), Senzaki's life seems picture perfect as wedding bells seem imminent for he and his girlfriend, Kanna (Ai Katoh). But Senzaki is balking as he feels personally undeserving of such happiness. When a large ferry boat carrying 620 passengers and 195 flammable vehicles runs aground off the coast of Kagoshima, Senzaki is sent in to evacuate passengers before the boat sinks. As the clock ticks down, he and his buddy, Yoshioka, find themselves fighting to save lives, including their own, while Senzaki must exorcise his own personal ghosts.