MysterywriterJanetFrobisherlivesaloneinadarkEnglishcountryhouse,whenshe'snotphilanderingwithhersecretary'sfiancée.Atanextremelyawkwardmoment,shehasanunwelcomevisitorGeorgeBates,whoclaimstobethepartnerincrimeofJanet'sestrangedhusband.GeorgeinsinuateshimselfintoJanet'shomeandlifedespitehereffortstogetridofhim;thetangledrelationshipsdevelopintoamacabre,murderouscat-and-mousegame.