Someone is trying to sabotage the rebuilding of Roulsville, which was destroyed after the flood caused by the breaking of the Roulsville dam. Mysterious accidents have injured workers and set back the construction of the new homes. Peter is called by the foreman to investigate the sabotage. While he is on the premises, Peter is attacked by an unknown assailant and is nearly buried alive underneath a pile of dirt. Peter is hospitalized in serious condition, and Judy devotes her energy into uncovering who is responsible for the accident. A piece of plastic that Roberta found at the construction site may be the key to uncovering the culprit behind the accident. As Judy investigates this lead, she comes face to face with the suspect and must use all of her wits to survive!