The story takes place in a luxury apartment in Wako, Saitama. A resident of Apt. 301, Shinichi Tonelli is gathering mistakenly scattered keys of his laptop. Another resident of Apt. 302, Jiro Kasuya is watching him through a peep hole. Swallowing his laughter, Jiro enjoys it as his daily hobby. One day, his daughter Akane finds out about his hobby.