Fake psychic Blanche Tyler and her boyfriend, George Lumley, attempt to locate the nephew of wealthy, guilt-ridden, elderly Julia Rainbird.

Meanwhile, it has been revealed to the viewers that Shoebridge murdered his adoptive parents and faked his own death and is now a successful jeweler in San Francisco known as Arthur Adamson.

He and his live-in girlfriend Fran kidnap millionaires and dignitaries, confining them in a secure room in the cellar of their home, and return them in exchange for ransoms in the form of valuable gemstones.

Arthur conceals the latest ransom, a large diamond, "in plain sight" within a crystal chandelier hanging above the home's main staircase.

George must go to work driving his taxi for an evening shift, so Blanche tracks down various A. Adamsons in San Francisco, eventually reaching the jewelry store as it closes for the day.

Lehman had incurred the director's anger by declining an offer to write the screenplay for No Bail for the Judge, a thriller set in London intended to star Audrey Hepburn, Laurence Harvey and actor John Williams.

By September 1973, Ernest Lehman had been persuaded to do the adaptation again — Hitchcock explained that he intended to keep only the bare-bones of Canning's novel and to relocate the story from England to California.

[6][7] Hitchcock, who often liked to specify the locales of his films by using on-screen titles or by using recognizable landmarks, deliberately left the story's location unspecific, using sites in both San Francisco and Los Angeles.

Hitchcock considered such actors as Burt Reynolds and Roy Scheider (for Adamson), Al Pacino (for George), Faye Dunaway (for Fran), and Beverly Sills and Goldie Hawn (for Blanche) for the film.

[9] Released in the year of the United States Bicentennial, Family Plot was chosen to open the 1976 Filmex (Los Angeles International Film Exposition) to honor American cinematography.

"[11] Roger Ebert gives the film three out of four stars, saying of it: "And it's a delight for two contradictory reasons: because it's pure Hitchcock, with its meticulous construction and attention to detail, and because it's something new for Hitchcock—a macabre comedy, essentially.

Masterfully controlling finely-tuned shifts from comedy to drama throughout a highly complex mystery-suspense plot, Hitchcock has created a film that has the involving detail work and teasing fascination of a novel to be read in front of a crackling fire on a rainy evening.

"[13] Charles Champlin of the Los Angeles Times praises the film as "atmospheric, characterful, precisely paced, intricately plotted, exciting and suspenseful, beautifully acted and, perhaps more than anything else, amusing.

"[15] Richard Combs of The Monthly Film Bulletin praises "the compact allusiveness and crisp elegance of Ernest Lehman's writing, which so deftly builds its own tongue-in-cheek attitudes into the material," and found that Bruce Dern and Barbara Harris made "a delightfully nuanced comic duet.

"[16] Dave Kehr of the Chicago Reader calls the film "[A] small masterpiece, one of Hitchcock's most adventurous and expressive experiments in narrative form.

Gene Siskel of the Chicago Tribune gives the film two-and-a-half stars and calls it a "disappointment", finding that it "descends into dull jokes, plastic characters, and a television sitcom conclusion.

"[18] Gary Arnold of The Washington Post calls the film "a chore to sit through", adding, "Lehman and Hitchcock are trying to recapture the old magic, but they've lost their touch.

The site's critical consensus reads: "The Master of Suspense's swan song finds him aiming for pulpy thrills and hitting the target, delivering a twisty crime story with pleasurable bite.