There is a mysterious department in the Hong Kong Police Force called the "Seventh Operations Group" that specializes in investigating mysterious cases that cannot be explained by science and never claims its existence. After one supernatural event after another, people can't help but question whether there are some things in the world that cannot be explained by science. A hard-working detective and a crazy mentally ill Maoshan master, the two of them sparked a spark and jointly investigated the urban legends that Hong Kong people are familiar with...