The 'Naruse' and 'Iizuka' families, who live next to each other in an apartment building, have built a close relationship through years of neighborly interaction. One day, a young and beautiful woman named Kokumi marries into the Naruse family. Iizuka, who has known the Naruse family's son since they were children, rejoices at his marriage as if it were his own. However, the intense sounds of the couple's nocturnal activities seeping through the wall gradually rob Iizuka of his sanity. Eventually, Iizuka comes to want Kokumi for himself and invites her to his home, where he gives her tea laced with sleeping pills…
