This is my entry into -Tigress-'s Plot Prompt Contest ;) I've never entered a contest before so I'm super excited!!!!! I hope I can do a good job ;P

My prompt is this;

"A group of friends go on a Summer retreat. Char:A family has owned the mansion for centuries, but it has not been inhabited for about a decade. When they get there, they find markings on the walls, and Char:B claims the markings are moving. No one believes him, LEAST of all Char:C...until strange things begin happening. They find a calendar that is reversing in days, disappearing as they go."

(prompt belongs to DGNA_Forever)