ADA reports that she was attacked by the sex maniac from behind and she fainted. YUNG gets an idea and they narrow down their scope of investigation to doctors and YUNG- finds that doctors have more chances to be close to their patients. After checking it is discovered that all the four victims were clients of St. Peter's Clinic. SUT, MING and CHAI are suspected as they' are doctors there. MAN is instructed to go to the clinic to bait the real murderer with “Envy”. She takes refuge in a unit being protected by the police. The killer arrives but is frightened by the alarm of the life which is out of order. YUNG sees the car of the villain and they focus on SUT and CHAI as they have the car of the similar style. It is found that SUT had bought a bottle of “Envy” near MAN’s unit and then he disappeared. It is rather certain that SUT is the sex maniac as the four victims’ records are found in his house.… ...