Troublesome Night 17

Original title: 陰陽路十七之監房有鬼

Gay has been arrested for possessing drugs and is sent to prison. When Mrs. Lung visits him, she realizes that a demon is following him around, and sends Yan into the prison to help Gay. With the help of the warden, they discover the demon is a vengeful ghost of a woman whose husband was wrongfully imprisoned there, and committed suicide. All she wants to see is his grave, which should be behind the prison. But when they can't find his burial site, she unleashes her pure wrath, and no one is immune from her rage.