Joseph Cotten returns to New York to visit his brother’s second wife and widow (Jean Peters); his timing proves inopportune, as his young niece goes into convulsions and dies in hospital. Cause of death remains a puzzler until a family attorney (Gary Merrill) reveals that Peters stands to benefit should both her stepchildren predecease her (a stepson may be next on her list). Though Cotten carries a small torch for Peters, his concern for the surviving son wins out, and an autopsy shows the girl died of strychnine poisoning. Peters ends up going to trial but is acquitted. Cotten, however, remains unconvinced, and, unbidden, joins Peters and his nephew on an ocean liner bound for Europe. He hopes to unearth the truth by means of trial by ordeal….
Surprisingly convincing, Peters takes on the role of a reserved society wife (as with most of Howard Hugues’ `protegees,’ she had more sides to her than the ones her Svengali wanted seen). As her housekeeper who also falls, albeit briefly, under suspicion, Mae Marsh turns up the luminous star of D.W. Griffith’s Judith of Bethulia, Birth of a Nation, and Intolerance (she was donning many a lace cap as a string of maids in this Indian Summer of her stardom).
Stone keeps the movie running along at a good clip and keeps tilting the ambivalence to the very end (Is Peters a wronged woman or a murderous monster? Does Cotten have a buried agenda of his own?). To be sure, certain coincidences and turns of plot don’t bear prolonged scrutiny, but they’re not allowed to become incapacitating lapses of logic, either. Blueprint for Murder meets the minimal production codes for suspense.