Shanghai, 1934. In an insect world parallel to that of humans, veteran Inspector Sun, a lone spider, leads his last mission against his archenemy the Red Locust, before embarking on a well-deserved retirement. His vacation aboard a Pan Am clipper between Shanghai and San Francisco comes to an abrupt end when millionaire Dr. Spindelthorp is found murdered. What begins as a routine case for Sun will ultimately decide the fate of humanity..