Professor Lo Yeung-guo (Hou Yao) and his students escape death from the Japanese army, and call on villagers in the countryside to form a guerrillas group. His son Lo Yung (Lau Hark-suen), however, indulges in debauchery. Entrapped by the Japanese, chicken-hearted Yung leaks information about the guerrilla that leads to deaths and injuries in the group. Yeung-guo reprimands his son for being an invisible traitor, inflicting even more harm than an outright traitor. Placing righteousness before family, he decides to execute his own son. As a writer-director-actor in the film, Hou Yao proclaimed his unwavering stance on resistance on the screen, and delivered a scathing attack on the cowardly ‘invisible traitors‘ at that time. Not long after, Hou was sadly arrested and executed by the Japanese army in Singapore.