After the death of his son, Fan Kwok Sang develops a mental disorder and accidentally kills his wife, Wai Ling, in front of her mother. He was then committed to a psychiatric hospital and after three years Dr. Chow Ming Kit believes Fan is ready to be released . However, Fan can’t adjust to his new life, especially with his Mother-in-Law paying often, troublesome visits. Dr. Chow begins to obsess over Fan’s treatment to preserve his status and reputation.
There is a very thin (Line?) between sanity and insanity.