Cheung Kei-sang (Myolie Wu) and the orphan Chau Sai-kai (Edwin Siu), two young lovers from a village in Southern China, are forcibly separated on their marriage day due to the Japanese invasion. Filled with hatred and vengeance, Sai-kai joins a Kuomintang secret agency, becoming their spy. Meanwhile, Kei-sang ends up in a Communist guerrilla militia and receives training to be their government's spy. She takes up a different identity as a Cantonese opera performer and cozies up with many Japanese officials, to the point of selling her body to extract military intelligence. She also meets Kong Sheung-hung (Wayne Lai), another Communist spy, and together they go on a mission to search for a Japanese businessman, who is linked to the war...