Satomi Shinobu and Inokuma Yuki work as detectives in the Mobile Investigation Unit of The Tokyo Metropolitan Police Department. The two are assigned as partners on the job and consider each other as rivals. However, once off the job, they are a couple but they keep their relationship a top secret. One day, Shinobu and Yuki were at the site where a dead body was found. There, they encounter a mysterious beautiful woman named Tachibana Kara. Soon, a series of bizarre crimes involving gruesome murders begin to occur; and strangely, Kara always appears at these crime scenes. Together, Shinobu and Yuki attempt to find the truth behind the serial murder cases and uncover Tachibana Kara's identity.