Doctor Sumida, who attended the medical seminar in Numazu, Shizuoka Prefecture, is found dead at a hot spring inn. Detective Kyosuke Otsuka (Hiroaki Murakami) of the Shizuoka Prefectural police arrives at the site with rookie partner Detective Misaki Tamura (Ayame Gouriki). They are certain that Doctor Sumida was murdered and they find a threatening letter among Doctor Sumida’s belongings. The two detectives travel to Tokyo.
At a park in Tokyo, a murder takes places. Detective Kouhei Suda (Takanori Jinnai) of The Tokyo Metropolitan Police Department arrives at the crime site. The victim also attended the same medical seminar which Doctor Sumida attended. Detectives Kyosuke, Misaki and Kouhei work together to catch the murder.