White Snake has come to Hong Kong to escape her lover Black Snake. To lure her out, Black Snake and Green Snake go on a murder and seduction spree in the big city. Police Officer Wang takes up the case, recovering a mysterious stone from a crime scene. He seeks advise from reclusive snake expert Professor Chen who explains that it's a rare fossil of snake eggs. Meanwhile, Black Snake begins falling in love with Officer Wang while Professor Chen finds himself with a mysterious beautiful new assistant who claims to be a student of Human Psychology from Beijing...