In the sixth installment of Taisho Roman Tanteitan, Kai Todo, "the Japanese Sherlock Holmes," takes on a serial murder case.

Kakeru, a former elite runner at high school, is chased for stealing food. He is saved by a Kansei University student Haiji, who is also a runner. Haiji persuades Kakeru to live in the old dormitory "Chikusei-so" where he plans to team up with fellow residents to enter the Hakone Ekiden relay marathon, one of the most prominent university races in Japan. Kakeru soon finds out that all of the residents except for Haiji and himself are complete novices.