Meet Penny Padgett, a twenty-seven-year-old cartoonist in Philadelphia who agrees to pet-sit a very peculiar cat named Godfrey. At first, he’s a warm and affectionate companion. Godfrey follows Penny all around the house and insists on sleeping by her side every night. But soon strange things are happening. Penny is haunted by disturbing and violent nightmares. There’s a terrible insect infestation in her basement. Her cute cartoon illustrations turn dark and surreal, as if influenced by some invisible hand. And her health starts failing, as if her mind and body are under attack by a sinister, malevolent force.