The “Academy Island Incident” in which four “kings” cross paths… Since then, Silver Clansmen Kuroh Yatogami and Neko have been searching for their master, Shiro. Without finding any clues to Shiro’s whereabouts, the two became disheartened. However, one day, they see HOMRA members Rikio Kamamoto and Anna Kushina being chased by someone.

The Nereus is a fifty-year-old Ice Breaker, salvaged by an idealistic crew on a mission to catch illegal fisherman. On chase, the crew find themselves well off-course and bearing down on a body mysteriously floating in the middle of the Devil’s Sea. Superstitious or not, the team soon discovers they’ve rescued a deadly creature feeding on the lifeless body. Their new mission—kill or be killed and preferably before they hit land.