How do inmates in a correctional facility satisfy their sexual desires? A full-fledged confined-space erotic story depicting the precarious prison life of prison guards and inmates involved in sex penpals begins!

Eun-ji and Shin-ae are lesbian lovers. However, Eun-ji is forced to marry Jae-seong due to her parents' torches. Due to Jae-seong's severe paranoia, he suspected his wife Eun-ji, who is unhappy with their marriage, of her relationship with Ho-jeong, Shin-ae's senior, who lived next door. With the help of Shin-ae, Eun-ji divorces Jae-seong, and Shin-ae approaches him for Eun-ji's revenge.