Kim Stanley plays a crooked medium who has become slightly unhinged since the death of her son. Craving money and publicity, she concocts a scheme with her weak-willed husband (Richard Attenborough). The pair will kidnap a wealthy young girl, collect the ransom, then use her "powers" to help the parents locate the child. The scheme falls apart, but not in the way that anyone might expect. Adapted by director Bryan Forbes from a novel by Mark McShane, Seance on a Wet Afternoon is a compelling psychological melodrama made doubly powerful by Stanley's mesmerizing performance.
~ Hal Erickson, All Movie Guide