Alfred Hitchcock's final film was adapted from Victor Canning's novel The Rainbird Pattern by Ernest Lehman, who previously wrote the screenplay for Hitchcock's North by Northwest. Barbara Harris plays Blanche, a phony psychic, hired by wealthy Julia Rainbird (Cathleen Nesbitt) to trace the whereabouts of her nephew, who'd been given up for adoption years earlier and who is now heir to a fortune. Blanche's cohort is "investigator" Lumley (Bruce Dern), who is fully prepared to milk the last dollar out of Julia before locating the long-lost nephew. Meanwhile, we are introduced to elegant kidnappers Adamson and Fran (William Devane and Karen Black). The fates of the two couples are inextricably intertwined by the search for the missing heir.
by Hal Erickson synopsis