Set in the remote Mitchell’s Inn in the Catskills, An Unwanted Guest follows a group of guests who arrive for a peaceful weekend retreat, only to find themselves trapped by a snowstorm. When a guest is found dead, it appears to be an accident. However, as more guests die, it becomes clear that a murderer is among them. With no way to contact the outside world, paranoia escalates as the remaining guests try to uncover the killer's identity before it's too late.