Ghost Killer in the Fog City

The rain at 12 o'clock in the middle of the night was like a torn curtain, hitting the glass windows of the old bungalow. Li Mu clutched the envelope that he dug out from the bottom of his grandfather's relic box, and rubbed the yellowed kraft paper with his fingertips. There was no sender on it, only a line of faded pen writing. "Don't start it until the rain stops on the seventh day."