Arsenic and Old Lace

Mortimer Brewster, a theater critic, marries his neighbor Elaine Harper on Halloween. The couple plans a Niagara Falls honeymoon, and their wedding marks the start of a string of unsettling family dynamics that will soon surface.

Elaine Harper travels to her father's house to share the good news of her marriage with her minister father. The visit underscores the contrast between normal domestic life and the Brewster family's hidden strange traditions.

Back at the Brewster residence, Mortimer breaks the news of his marriage to Abby and Martha. The aunts respond with cheerful complicity, hinting at the bizarre secrets that will soon surface about the family.

While researching notes for his next book, Mortimer stumbles upon a corpse hidden in the window seat. He initially suspects that Teddy's delusions may have produced a murder rather than a ghost.

Abby and Martha confess to murdering Mr. Hoskins and other bachelors as part of their so-called charity. They post a 'Room for Rent' sign to lure victims and serve elderberry wine laced with poison, then bury the bodies in the cellar.

To keep the corpses hidden, Teddy carries Mr. Hoskins' body from the window seat down to the cellar, further concealing the growing tally of victims. His actions are driven by his belief that they are curing yellow fever victims.

To protect the aunts from discovery, Mortimer frantically goes to file paperwork to commit Teddy to the Happy Dale mental asylum. This move escalates the tension as he leaves the house under the pretense of safety.

Jonathan, a serial killer with a battered past, arrives with his alcoholic accomplice Dr. Herman Einstein. Einstein’s work has altered Jonathan’s appearance, and they hide Spenalzo's body in the window seat as part of their plan.

Mortimer returns to confront the intruders and, to his horror, learns that Mr. Hoskins’ body has already been located in the cellar. The tense confrontation intensifies as the criminals reveal their broader killings.

Mortimer visits Elaine to share his growing reservations about marrying into a family he finds dangerously insane. Elaine listens, torn between concern and loyalty to the marriage.

Officer O’Hara arrives in response to neighbors’ complaints about Teddy's bugle blasts. Einstein distracts Mortimer by claiming he is enacting a scene from a play, while Jonathan attempts to kill O’Hara but is knocked out by Einstein.

Lieutenant Rooney arrives, and Jonathan is arrested after admitting there are thirteen bodies buried in the cellar. The aunts insist on joining Teddy for their next step, while Einstein flees after signing the aunts' commitment papers.

Abby and Martha reveal that Mortimer is not actually a Brewster; his mother was the family cook and his father a chef on a steamship. The revelation awakens in him a new sense of outsider status within the family history.

Elaine is horrified when she discovers the corpses in the cellar. Mortimer silences her with a kiss and whisks her off on their honeymoon, determined to leave the madness behind.