The Thin Woman - Ellie Haskell - is back, in the most mischievous, marvelous mystery to hit the marital pike yet. Ellie's mum-in-law Magdalene has moved in permanently and poor Ellie finds herself up to her formerly fat neck in crocheted doilies and cheap statues of Catholic saints. As Magdalene runs her finger over every surface in Merlin's Court (checking, undoubtedly, for dust), Eillie discovers that she isn't the only woman in Chitterdon Fells with the ultimate mother-in-law problem - three others are experiencing the same living hell. One tipsy evening, four imaginary plots to bump off the resident in-laws are hatched and those plots start coming lethally true in real life. Ellie once again plunges into a desperate chase to outwit a killer.