Ryo Saeba works Tokyo's Shinjuku as one half of City Hunter, a freelance sweeper team hired by clients who chalk the code 'XYZ' on a station message board. A crack shot and an incurable womanizer, he works alongside his partner Hideyuki Makimura until Hideyuki is killed, leaving Ryo to look after Hideyuki's younger sister Kaori. She steps in as his new partner, and a giant hammer settles the matter whenever his lecherous side gets out of hand.