In Episode 4, Mashiba Aya, one of the main characters, becomes infected with a parasitic bug after a torrid sexual encounter. The parasite takes control of her body, amplifying her insatiable urges and turning her into a threat to her friends. The only known antidote is stored deep within the labs of the Koga Institute, a rival ninja faction.
The episode follows Yatsurugi Shinobu, Aya's best friend, as she embarks on a dangerous mission to retrieve the antidote and save Aya. Along the way, Shinobu faces numerous challenges, including battles with Koga ninjas and her own internal conflicts. The story is filled with intense action sequences, supernatural elements, and explicit scenes, maintaining the series' signature blend of eroticism and ninja-themed drama.
