The McMillan children, Jack and his twin sisters Eva and GG, are excited to move into their new house, a mansion from the late 1800s. They get even more excited when their new neighbor, Roman tells them the house contains a mystery! But that excitement morphs into frustration when they keep getting blamed for mischief they didn't cause, then becomes pure fright when they find out the true perpetrators. Yes, the house is infested with some sort of creatures from another realm! But what kind of creatures? And can they be sent back to their place of origin? And, most importantly, HOW?

Through wild animal noises in the night, flying objects, blackouts, house-quakes, unexplained messes, logic-defying monsters and more, the four children and their two pups run for their lives and solve the mystery of the original owners of the house, their legacy and the strange character who obsessed over it all until he became a part of the whole unfortunate circumstance.