[Mosaic Removal] The Naruse family and the Iizuka family, who live next to each other in an apartment building, have built a close relationship over many years as neighbors.One day, a young and beautiful Kokomi marries into the Naruse family.Iizuka rejoices at the marriage of the son of the Naruse family, whom she has known since childhood, as if it were her own, but the sounds of a happy married couple leaking through the walls in the middle of the night gradually steal away Iizuka's rationality.Then, Iizuka, who wants to make Kokomi his own, calls her to his home and makes her drink tea containing sleeping pills.