Nana and Shota are a newlywed couple and Nana is 15 years older than Shota. They both enjoy mystery. The newlywed couple then move to an apartment and they attend a resident's meeting there. Nana and Shota become involved in murder cases that take place at the apartment. Residents get murdered one by one. Some residents have a motive, but those suspects have an alibi. Because of this, an arrest has yet to be made.