A schoolgirl, Siu-Man, has committed suicide, leaping from her twenty-second floor window to the pavement below. She is an orphan and her older sister refuses to believe there was no foul play. She contacts a man known only as N., a hacker, and an expert in cybersecurity and manipulating human behaviour. What follows is a cat and mouse game through the city of Hong Kong and its digital underground. Film rights bought by Wong Kar Wai.