Junichi Narutaki is a close friend of Yoichiro Tatsumiya and harbors romantic feelings for Yoichiro's sister, Yukari Tatsumiya. He actively fights to defend Tokyo against the antagonist Yasunori Kato, driven particularly by his desire to protect Yukari. Narutaki joins the Tsuchimikado Clan during their initial clash with Kato and later aids in defending the Tsuchimikado temple when Kato attacks to kidnap Yukari.

During the Great Kanto Earthquake of 1923, Narutaki partners with Koda Rohan to enact defensive spiritual measures. Together, they deploy the Chart of Eight Directions, a form of Kimon Tonkou sorcery, at Nihonbashi Bridge to trap or delay Kato as he advances toward the grave of Taira no Masakado.

Later, around 1927 during Tokyo's reconstruction, Narutaki maintains his connection to the Tatsumiya family. He participates in their efforts to protect Yukari's daughter, Yukiko Tatsumiya, from Kato's renewed kidnapping attempts, demonstrating his ongoing commitment to safeguarding the family.

Narutaki also appears in the sequel *Tokyo: The Last War*. His character consistently functions as a supporting figure within the ensemble opposing Kato's destructive ambitions, motivated by loyalty to the Tatsumiya family and his unrequited affection for Yukari.