An exceptional marksman and hopeless playboy, private eye Ryo Saeba reluctantly forms an alliance with his late partner's sister to investigate his death.

Follows Ryo Saeba, a "sweeper" who navigates the shadowy depths of modern-day Shinjuku, Tokyo. Balancing a cool demeanor with a fun personality, Ryo takes on high-stakes challenges in the underworld. After receiving the message "XYZ, please find my sister," Ryo and his partner Hideyuki go on to search for Kurumi, a famous cosplayer. Meanwhile, mysterious violent incidents are taking place in Shinjuku, and Saeko, a skilled police detective is having a tough time solving these cases. Ryo and Hideyuki work in tandem to pursue Kurumi, but tragedy strikes when Hideyuki is killed during the investigation. Witnessing her brother's death, Kaori implores Ryo to uncover the truth behind the incident.