Haneda, the president of a company dealing in gold, is shot to death on the Raicho 9 limited express from Osaka to Kanazawa. Detective Kamei begins an investigation in cooperation with the Fukui Prefectural Police. In the Green Car, Detective Nishimoto had noticed a beautiful woman talking to the victim just before he was killed. Looking into her background, she turns out to be Yumiko Miura, living in Setagaya in Tokyo. An eyewitness who claims that she is the murderer also appears, and she is taken into custody. Before long, the victim's unexpected relationships will be revealed one after another...

In the suburbs of Tokyo, Ogawa, a 39-year-old programmer, lives alone in a 50-year-old apartment. Since the onset of the COVID-19 pandemic, Ogawa has been working entirely remotely, rarely leaving his home or meeting other people. At first glance, his life might seem the epitome of solitude. Yet, his days are fulfilling, occupied by hobbies like playing the digital piano, online mahjong, and tinkering with keyboard switches. Despite his contentment with this solitary lifestyle, Ogawa has been a member of a marriage agency for the past three years. One day, through the agency's app, he receives a message from a woman named Maeda. Little by little, change begins to ripple through Ogawa's quiet life.