A girl and her brother are spending summer vacation with their grandmother. Their troublemaker cousin, Robert, is there, too, and one day, he dares the kids to poke around what seems like an abandoned house. The kids have the fright of their lives when they think they see a ghost! But the ghost turns out to be Mr. Peterson, an old man who lives alone. The kids form a friendship with the old man and his old house. So they are devastated when Mr. Peterson is suddenly taken into a retirement home and his house emptied out. But what can they do?