In 2003, after a collision with a truck, a double-decker bus veered off a bridge and plummeted 35 meters into a village below, claiming 21 lives. Ten years later, sightings of a female ghost dressed in red have been reported at the site of the horrific accident. Poon, the host of the radio show "Twilight Online," discovers the identity of the ghost -- a College teacher named Lui. He decides to visit the village to conduct a paranormal investigation. A male teacher and four female students from the school decide to help out, believing that Lui's spirit has returned to resolve unsettled grievances. One evening, the students sense the presence of the ghost and start disappearing one by one. Their bodies are later discovered. They all died from a horrible death. Meanwhile, inspector Gu and his new sidekick Bee have been assigned to investigate the sightings of a female suicide victim.
Lu Ming Zhe, a police inspector is forced to take justice into his own hands when he seeks to arrest Cao Nan, the ringleader of a criminal gang. Against Ming Zhe’s better judgment, he agrees to use his childhood friend and ex-convict Tao Cheng Bang as an informant, but nothing can prepare them for the impending storm.
Ann Hui’s darkly realistic Night and Fog starts at the end of the story: a man murders his wife and, based on statements by unreliable witnesses, the film goes on to investigate how things could have got this far and what kind of man was able to kill his family.