The placid village of Lymstock seems the perfect place for Jerry Burton to recuperate from his accident under the care of his sister, Joanna. But soon a series of vicious poison-pen letters destroys the village's quiet charm, eventually causing one recipient to commit suicide. The vicar, the doctor, the servants - all are on the verge of accusing one another when help arrives from an unexpected quarter. The vicar's house-guest happens to be none other than Jane Marple.