Marcus Grimm is a paranormal investigator who has made a living determining if supernatural events are occurring. Although he has a special intuition and connection to the Otherworld, he remains a skeptic, which allows him to figure out if there is a genuine event or if a family is trying to get their fifteen minutes of fame.
When Marcus meets John Billings and his children at their house, he has a sense that the events John describes are very real. As Marcus explores the house for signs of supernatural activity he not only learns more about himself, but uncovers truths that will change his life forever. And he discovers that sometimes accepting invitations can have dire consequences.