Ruth Earlton and her fiance Dr. Ted Carver arrive at her father's house soon after his death. There they find her invalid Uncle Robert, the housekeeper Mrs. Krug and the housekeeper's son Hanns. Ruth learns a chimpanzee her father used in experiments is still kept in the basement. Earlton's will leaves his estate to Ruth, but it will go to Uncle Robert in the event of her death. Small monthly sums are left to the housekeeper and her son. When Ruth goes to bed that night, a large, hairy hand reaches through the headboard and attempts to strangle her. She screams; it disappears. Ted and Mrs. Krug arrive at her room to comfort her. Ted gives her a sedative, and she falls asleep in a chair. Mrs. Krug stays with her, taking the bed. The hairy hand reappears through the headboard and strangles Mrs. Krug. Ruth awakens and alerts the rest of the household. Afterward, Hanns meets with Robert in secret, who tells him that their plan to kill Ruth has failed and Hanns has accidentally murdered his own mother. Hanns blames Robert for this, and after mentioning that Robert is actually his father, he strangles him as well, leaving him for dead. Hanns takes Ruth to the ape, but the ape grabs him.
—Garon Smith