After absorbing supernatural powers that saw his powers increase tenfold, taxi driver Ma Gwai continues on another adventure as a past incident involving a childhood friend comes back to haunt him.

Ma Gwai's childhood friend Ho Zai died when he was only 8 years old due to a drowning accident. With unfinished business, the ghost of Ho Zai approaches Ma Gwai and appears to him in different forms. Meanwhile, Ma Gwai's story with Dr. Felicity Chong has yet to reach a conclusion but a thousand-year-old sea spirit may come between them.