Jonathan is a middle-aged grounds keeper at a local theme park and suffers from a debilitating case of OCD. One day, he has his daily routine altered after a pair of girls breaks into his creepy abode, filled with taxidermy specimens, to take selfies, and one winds up dead. Instead of reporting the incident, he keeps the corpse and turns it into a friend.
A trashier film would have gone down the necrophiliac route for the cheap shock value, but Decay treats the situation with far more tact and sensitivity.