On a dark and stormy night in the 1930s, a group of guests travels to an isolated country estate to hear the reading of the will of the wealthy Sinas Cavinder. The attendees include Burling Famish Jr. Brian Howe and his wife Pristy Christine Romeo; Pristy’s dim-witted lover Teak Armbruster Kevin Quinn; big-game hunter Jack Tugdon Jim Beaver; the foppish Lord Partfine Andrew Parks; elderly Mrs. Hausenstout Betty Garrett; kindly Seyton Ethelquake James Karen; and Cavinder’s ward, the fragile Sabasha Fanmoore Fay Masterson. They’re joined by rival reporters Eight O’Clock Faraday Daniel Roebuck and Billy Tuesday Jennifer Blaire, along with cab driver Happy Codburn Dan Conroy, and the party grows by two with psychic Mrs. Cupcupboard Alison Martin and the stranded motorist Ray Vestinhaus Larry Blamire.
The gathering settles in the parlor as lawyer Farper Twyly Mark Redfield prepares to read the will. Before he begins, the guests note a string of ominous hints: Sabasha has been receiving death threats, a serial killer known as the “Cavinder Strangler” is still at large nearby, and tonight is also the night a 300-year-old ghost said to be Sarah Cavinder might return.
Twyly’s reading reveals a mixed distribution: some guests receive small, trivial gifts, while others stand to gain larger sums. The bulk of the estate goes to Sabasha, but with a stipulation that upon her death the estate will pass to Burling. An amended letter supposedly modifying the will is mentioned, but the letter has been stolen, and Twyly insists that only he knows its contents. Before he can reveal more, the lights go out, and when they return, Twyly is found stabbed to death.
Ray explains that the only bridge back to town has collapsed behind him, so Farady and Tuesday propose waiting for morning’s arrival of the police. At midnight, however, Pristy is strangled by a masked killer. Dr. Van Von Vandervon [H.M. Wynant] arrives, explaining that he tracks an escaped lunatic to the house, though his unusual profession (therapist and patient never meeting) makes it unclear what the patient looks like or even their gender.
The night unfolds as the survivors scramble for the missing letter and clues to identify the killer. A seance is held by Mrs. Cupcupboard, but the spirit yields no help. Mrs. Hausenstout appears at times with a gorilla in tow—the gorilla is Bob Burns. A police inspector [Tom Reese] is also present—and promptly killed. As events spiral, Jack Tugdon [Jim Beaver], Teak Armbruster [Kevin Quinn], Seyton Ethelquake [James Karen], and Dr. Van Vandervon [H.M. Wynant] are murdered, followed by Archie Folde [Robert Deveau], the estate’s cook.
Happy discovers a woman locked in an attic room. Although the group assumes she is Sarah Cavinder’s ghost, Jane Hovenham [Trish Geiger] explains that the captive is Thessaly [Susan McConnell], Sinas Cavinder’s daughter. Thessaly also knows the letter’s contents and reveals that it makes Thessaly, not Sabasha, the rightful inheritor of the estate.
Faraday [Daniel Roebuck] and Tuesday [Jennifer Blaire] uncover the truth: Burling [Brian Howe] and Sabasha [Fay Masterson] had been scheming separately but eventually joined forces to eliminate rivals for the inheritance. They also deduce that the real Sabasha is dead and the woman posing as her is actually Dr. Van Vandervon’s escaped lunatic.
Burling threatens to blow up the house unless Faraday and Tuesday hand over the letter, but is accidentally electrocuted when confronted by Thessaly. Ray reveals his true identity as Bax Tremblay, an undercover police investigator. He, Faraday, and Tuesday pursue the false Sabasha, who ends up strangling herself to death to avoid capture.
By morning, Thessaly takes possession of the estate. Faraday proposes to Tuesday, and she accepts, agreeing to share their newspaper “scoop.” They are driven away by Happy, who finally admits that the cab meter ran all night and that he is owed a substantial payout—$87.42.
