Family Plot

Family Plot is a 1976 American dark comedythriller film that was the final film directed by Alfred Hitchcock. The film was based on Victor Cannings novel The Rainbird Pattern, which Ernest Lehman adapted for the screen. The film stars Karen Black, Bruce Dern, Barbara Harris and William Devane. The film was screened at the 1976 Cannes Film Festival, but was not entered into the main competition.

A fake psychic, Blanche Tyler Barbara Harris, and her boyfriend, George Lumley Bruce Dern, attempt to locate the nephew of a wealthy and guiltridden elderly woman, Julia Rainbird Cathleen Nesbitt. Julias deceased sister gave the baby boy up for adoption, but Julia now wants to make him her heir, and will pay Blanche 10,000 if the heir, Edward Shoebridge, can be found. George Lumley discovers that Shoebridge is thought to be dead, but he tracks down another criminal, Joseph Maloney Ed Lauter, who paid for the tombstone over an empty grave.Shoebridge murdered his adoptive parents, faked his own death and is now a successful jeweler in San Francisco known as Arthur Adamson William Devane. He and his livein girlfriend, Fran Karen Black, kidnap millionaires and dignitaries, returning them in exchange for ransoms in the form of valuable gemstones. Arthur conceals an enormous diamond in plain sight in their crystal chandelier. ........

Source: Wikipedia