The protagonist Masaru has just inherited a large amount of property after his father's death. However, people are trying to obtain it through any necessary means, even if it means killing him. Narumi helped Masaru avoid being kidnapped after struggling with strange characters. He discovered that they were not humans, but wooden puppets with astonishing power. After a difficult struggle, Narumi was forced to admit that he was not their opponent; Just as he began to believe that Masaru would be captured, Masaru's defender Shirogane came here from France with a weapon - the puppet Arlequin. The story of the Karakuri Circus begins here.
出生在海里，守护着大海，走向大海——那就是蓝色的美人鱼！为了维护海洋安全，专业的“蓝美人鱼”进入了位于山本的横须贺女子海洋学校。她被任命为“春日”号巡洋舰的船长，并与同学一起参加了一次海上实习。
