"There is no smoke without fire, that's what I say."

Jerry and his sister Joanna come from London to the small town of Lymstock, guests of Miss Barton. They plan to stay with her for a while, until Jerry recovers from an airplane accident. However, shortly after their arrival, they receive an anonymous letter accusing them of not actually being siblings but lovers. Very soon, they learn that other people in the town have received similar letters. And although the accusations are always false, many people have been upset and some fear the worst.

It is time for the police to take on the case. But perhaps more effectively than an experienced detective, an elderly lady with a sharp eye, who knows better than anyone the art of gossip and the dark passions hidden in the quiet small towns of the English countryside, can solve the mystery: Miss Marple.