Having raised my only daughter Ichika with great care, I was heartbroken when she married and moved out. So I decided to boldly renovate our home into a two-family residence. My daughter and her husband were happy about it, and I believed we could now live together as one big family. But ever since the two-family arrangement began, my wife Maki's behavior has become strange. She frequently visits my daughter's side of the house, leaves home for no apparent reason, and clearly lies to meet my son-in-law, Shinji. Something is definitely wrong, and I intend to uncover the truth.