Arisu Kisaki is a sexually insatiable woman who remains unsatisfied despite having nightly sex with her husband, leaving her emotionally unfulfilled. She lives in a thin-walled apartment where her moans easily carry into the neighboring unit. Next door resides a man whose wife has recently returned to her parents' home after giving birth, leaving him alone and tormented by the sounds of Arisu's passionate encounters. One day, Arisu visits her neighbor, setting off a chain of events that ignites an intense and forbidden affair.