Rats (2016)

Bill is a middle aged antiquarian book specialist who arrives at Montague Castle to catalogue their more interesting volumes. But this academic has other things on his mind, he intends to spend a night of passion with Jess, one of his undergraduates. What better way to impress a girl than a night alone in a medieval castle? Only they aren't quite alone. Scratching noises can be heard through the walls and someone, or something, is watching. By the end of this night Bill will learn that within these ancient walls every action has consequences. Terrible, terrifying consequences.