Little Tommy Woodry (Bobby Driscoll) is a bright kid with a vivid imagination. He's always telling tall tales. Then, one night, he witnesses a brutal murder committed by his seemingly normal neighbours, the Kellersons. When Tommy tells his parents, they think it's just his over-active imagination. When he tells the police, they don't believe him either. Only the Kellersons believe Tommy. And now they're coming to get him.