In the lawless maze of Kowloon Walled City, Xia Liu Yi is one of the fiercest fighters around. To help launder money for his triad boss, he helps produce a film project and forcibly drags He Chu San, a college student, into writing the script. Chu San wants only to escape—but when a set collapses, Liu Yi dives in and shields him in his arms. Their fated encounter begins.

He Chu San takes meticulous care of the unconscious Xia Liu Yi and hides his whereabouts. The two begin an awkward cohabitation in a small room.