One day, Kenji is invited by fellow Kuonji student Natsuki Shinohara (Nanami Sakuraba) to participate in the 90th birthday of her great-grandmother Sakae Jinnouchi (Sumiko Fuji). After traveling to Sakae's estate in Ueda, Natsuki introduces Kenji as her fiancé to Sakae, surprising them both. Kenji meets several of Natsuki's relatives and discovers that the Jinnouchis are descendants of a samurai (vassal of Takeda clan) who challenged the Tokugawa clan in 1615. He also meets Wabisuke Jinnouchi (Ayumu Saitō), Natsuki's half-granduncle and a computer expert who has been living in the United States since stealing the family's fortunes 10 years ago.