When a violent murder leaves behind an unidentified body, father and son coroners Tommy and Austin Tilden are tasked with finding a cause of death for the local sheriff by the next day. Forced to work through the night, Austin cancels plans with his girlfriend Emma in order to help his father with the mysterious corpse. However, not long after starting their examination, a number of disturbing phenomena occur which leave Tommy and Austin facing a desperate fight to survive the night.