A missing police pistol is connected to a series of recent heists and murders. Its owner Wong vanished earlier while pursuing a suspect in the mountains. His partner Chi-Wai miraculously returned unharmed. Hotshot Regional Crime Unit inspector Ho is in charge of the serial murder investigation. He knows the only chance he has in cracking the case is to ask for help from his mentor/former boss Bun. Bun was recognized as a gifted criminal profiler until he went mad several years ago. Bun has the gift to see into a person's inner personality. This is where the subconscious desires, emotions and mental state are laid bare. For Bun, they are the key to unlocking a killer's identity. Bun comes to the conclusion Chi-wai has a total of seven personalities. The cop's alternate identities are responsible for his murderous behavior. However, Ho feels betrayed when Bun's investigation went beyond his imagination. What begins as a quest for answers has now taken a schizophrenic turn where truth and lies, reality and delusions intertwine.