As night arrives, the shadows of Koga fall on Iga and a new threat exists for our lusty vixens. After a torrid sexual encounter Yatsurugi Shinobus best friend Mashiba Aya is infected with a parasitic bug and succumbs to its will. Having the same insatiable urges, the same tragedy is about to happen to Kage Lena. The only known antidote is stored deep within the labs of the Koga Institute and is the only thing which will save Kage Lena. Our hero Shinobu, in attempt to recover the antidote, falls the victim to the many sexual traps found within the institute. Its now up to the rest of the girls from Iga to save both Shinobu and Kage Lena and theyll do Ëœanything to get the job done!