To celebrate their parents' golden wedding anniversary, the eldest son Tetsu and the second son Hiroshi returned to their hometown. Tetsu's wife Yumi and Hiroshi's wife Suzuka also gathered, and their parents were delighted. However, Hiroshi had been harboring feelings for Yumi and was at odds with the cold Tetsu. Similarly, Suzuka, who couldn't get Hiroshi's attention, was also dissatisfied. Thus, Hiroshi secretly approached Yumi while Suzuka vented her frustrations to Tetsu and began to seduce him. The couples secretly swapped partners, indulging in debauchery. Eventually, the four of them unexpectedly encountered each other…
