The "Death Investigation Extension (D.I.E.)" in the police force was established to accommodate those who have been sent away by their supervisors. As everybody knows, members of the Extension are to investigate unsolved cold cases. YUE CHI-LONG (Roger Kwok), who has cracked a large number of difficult cases by extrasensory means, is assigned to the D.I.E. believing that he will get promoted soon. Later LONG finds out that his supervisor still has a long way to go before he reaches retirement age. Hoping to leave the Extension as soon as possible, he gets to solve a lot of intriguing cases. New appointee YING CHING-CHING (Sonija Kwok) is a good-looking girl but she means to act tough and sassy in front of others. She takes an uncompromising stand over every case she deals with, which leads her into constant quarrels with LONG. The relationship between the pair is deteriorating day after day.
LONG's elder sister, YUE CHI-CHING (Margie Tsang), has been living with him. While investigating an old case, LONG gets to find his long-lost father YUE TAI-HOI (Leung Ka Yan). Through close collaboration with LONG, CHING-CHING has gradually developed affection for him. As she is still torn between LONG and her two-timing boyfriend SHING KA-TSUN (Kenneth Ma), LONG has started to try to avoid her without rhyme or reason. Feeling so confused about what is happening, CHING-CHING decides to do some probing and is shocked to discover that LONG has been dogged by a female ghost called SIU SIN (Kitty Yuen).