A household cook named Margie has a sudden mental breakdown and attacks her employers, the Holland family. After being briefly restrained, she escapes the house and later sneaks back in. Driven by a "fiendish idea," she takes the Holland's infant baby from its crib and hides the child in the kitchen oven before starting a fire beneath it. The parents unknowingly begin to use the oven, but the baby is rescued just in time when the parents discover the plot during a struggle with the cook, who is then arrested by police.