Rumi (Yoko Mihara) and Emi (Masayo Banri) are sisters who dance nightly at the Blue Moon cabaret, which happens be the headquarters of a drug ring. Offstage, Rumi captivates the gang boss, Iwahara (Shuntaro Emi); while Emi attracts the portly club manager, Yajima (Saburo Sawai). Meanwhile their older brother Shinichi (Ryo Kuromaru), a seaman, is unwittingly assisting Iwahara with his drug running. When Shinichi’s ship is sea-jacked by another drug gang, an outraged Iwahara suspects him of treachery and has him beaten and confined in a dungeon-like basement. Rumi and Emi try to free him, but a gang hitman discovers them - and their attempt ends in failure. Now under suspicion themselves, the girls try to escape, but luck goes against them and they are taken to an island where Iwahara and his crew plan to ambush the rival gang.