Natsuki Amakusa is a talented young detective with the Tokyo Metropolitan Police Department. One day, he meets Yuuya Shiki, a high school student with a mysterious ability to see "marks" on murderers.

After Yuuya helps solve a complex murder case, Natsuki decides to recruit him. The two team up as partners to investigate various criminal cases while working to uncover the mystery behind Yuuya's hidden power.

(Source: MAL News)