After the wedding of Eleanor Lindsay and Bob Lindsay, a doctor named Dr. Helen Jackson invites a select circle to her home to discuss changing her will. While she works in her office, her brother Zeno Jackson confronts her, insisting that during her visits to Africa she must have taken gold and hidden it in the office. In response, she hits a gong that summons the missing-link monster N'Gina, a creature she has kept hidden since a prior African expedition. Zeno leaves the room terrified, while the scene plants a shadow over the wedding that followed.
At the Lindsay wedding, a sudden explosion erupts, scattering guests and sending the party into a broader investigation of the house. Most attendees search the grounds and the ballroom, but Eleanor Lindsay remains at home, choosing safety in place and awaiting news. Later, [Dr. Helen Jackson] reveals a long-buried history: she had been in love with Eleanor’s father and fled to Africa after he married Eleanor’s mother, a revelation that adds a layer of secrecy to the already tense family dynamic.
Back in the laboratory, [Dr. Helen Jackson] works on a potion intended for the benefit of humankind. To everyone’s horror, the creature [N'Gina] drinks the potion and goes on a rampage, tearing through the scene and ultimately killing the doctor. The Lindsay family learns they are named beneficiaries in Jackson’s will, which fuels suspicion that their supposed inheritance came at a dangerous cost. Yet they are eventually acquitted of any murder charges and move into the eerie manor left to them by Helen.
As the days pass, [Eleanor Lindsay] notices food disappearing from the house, a strange pattern that feeds growing unease. [Bradshaw], the executor of the will, arrives to urge them to sell the estate, and in a moment of carelessness, he rings the gong tucked away in a desk—an action that brings [N'Gina] back to the surface from her cellar hiding place. The mystery deepens as [Detective Nelson] moves into the home to investigate, treating the case as one of possible supernatural menace as much as a family crime.
Zeno breaks into the couple’s bedroom, but the intruder escapes when [Eleanor Lindsay] accidentally strikes [Bob Lindsay] instead of the intruder, a twist that heightens the fear that someone—or something—inside the house is betraying them. When [N'Gina] finally creeps out of the basement, Zeno races along her path to seize Helen’s gold; the creature drags him upstairs, where the evidence awaits [Detective Nelson].
Eleanor spots the terrifying creature and faints, while [N'Gina] carries her toward the lower floors. Nelson discovers Zeno’s body as [Bob Lindsay] awakens and joins the search for Eleanor. A fire breaks out, sparked by the monster’s actions, and the two men race to the basement as Eleanor’s screams echo through the walls. Nelson fails to arrest [N'Gina], but [Bob Lindsay] manages to trap the beast in a cell as the house burns around them. In the ashes, Nelson emerges with the gold in tow, while [Bob Lindsay] and [Eleanor Lindsay] escape the inferno unharmed, stepping out into the night with their lives and the truth of the estate’s strange history. The tale remains a tense blend of gothic mystery and creature-feature danger, anchored by the fragile bonds of a family under siege.
