June and Naomi host a popular radio show as DJs, but after dark they serve as elite agents in a secret counter-terrorism unit under the code name the Siamese Cats. In an early twenty-first century Tokyo troubled by frequent terrorist crimes, the government has quietly set up this squad within the Cabinet Research Office. The pair gather intelligence and settle incidents faster than the police or the military can. The action film is the first animated adaptation of Monkey Punch's Siamese Cat.