"According to legend, there is a "barrier" on the top of a mountain in Sai Kung, a mysterious alien space similar to the Bermuda Triangle, which has caused many hikers to disappear mysteriously... The police sergeant disappeared after hiking alone on the mountain, and his daughter, a social worker, disappeared. He was still grudged and insisted on finding the truth, but to no avail for many years. When he disappeared for seven years, a madman..."