Maruyama couple and Sugawara couple meet for the first time and experience wife swapping under one roof. Maruyama Kenji and Ryoko participate hoping to break their marital routine. Ryoko joins with the mindset of doing anything for her husband, but she quickly becomes attracted to the other man. Meanwhile, Sugawara Hiroshi and Natsu are both first-timers in wife swapping, harboring strong sexual desires as they eagerly indulge in each other's bodies. By the final day of their three-day, two-night swapping experience, an intense four-way orgy awaits.