SKMJ-742 Congratulations on becoming a working professional! A brother and sister move to Tokyo for work and try bathing together for the first time in ten years, separated only by a towel! They shouldn't care about each other's gender, but they end up bathing together in the cramped tub! This extreme experiment makes them aware of each other's existence... The close brother and sister end up having unprotected sex!

A close brother and sister accept a challenge! A forbidden, secret surveillance project! A man and a woman, strictly forbidden from having sex before moving to Tokyo, are now forced to share a small bathtub for the first time in ten years. Will they cross the line and engage in unprotected sex?! The brothers enter the bathtub in their most authentic state, with a huge prize in front of them! Both are now adults. A heart-pounding mixed-gender bathing experience is about to begin!