Rosalind Russell stars in this marathon adaptation of the Eugene O'Neill play. The O'Neill original transposed Euripides' Agamemnon/Clytemnestra legend to post-Civil War New England. Russell plays the daughter of a returning war hero (Raymond Massey), who comes home to find his wife (Katina Paxinou) in the arms of a younger man. The wife murders the husband, leaving it to her grown children--Russell and Michael Redgrave--to exact vengeance. This morbid plotline climaxes with Russell's descent into destructive self-righteousness and her brother's retreat into insanity. Though superbly acted, Mourning Becomes Electra scared away too many moviegoers in its original three-hour running time, which was still half the length of the O'Neill play. Even when pared down to 105 minutes for general release, the film lost tons of money for the ever-beleaguered RKO Studios; to complete the film's curse, Russell lost her long-cherished (and never-won) Best Actress Oscar to Loretta Young for The Farmer's Daughter. According to Oscar legend, Russell was so certain of winning, on the heels of her husband's massive promotional campaign, that she was already out of her seat when she heard Young's name.