The eight-year-old son of Chamberlain Sano mysteriously vanishes. Sano discovers that Lord Matsudaira, his political rival, has had the boy kidnapped and sent to the northern frontier island of Japan known as Ezogashima (Hokkaido). Something is rotten there: Communications between Ezogashima and the capital have broken down. Sano and his wife Reiko travel to Ezogashima to rescue their son and find themselves caught up in big. Sano and Reiko must solve the murder if they want to escape Ezogashima alive.