Mana visits Sakaiminato where her aunt and uncle live. In order to cheer Mana up after she learns that the festival has been canceled, her uncle Shouji goes out fishing to catch her a lively fish, but he never comes back. Mana goes out on a boat with fisherman from town to search for him, and gets attacked by marine spirits on the open water. The ghost ships turn out to be Shouji and the other missing fishermen. When the boats are sunk, Mana is the only one to reach shore. Kitaro, who came to help, heads out to sea where mist from the boats rises. There, he and the marine spirits face a yokai that was supposed to have been sealed away, Umizatou.