Lymstock is a town with more than its share of shameful secrets -- a town where even a sudden outbreak of anonymous hate-mail causes only a minor stir. But all of that changes when one of the recipients, Mrs. Symmington, appears to have been driven to suicide. 'I can't go on,' her final note reads. Only Miss Marple questions the coroner's verdict. Was this the work of a poison pen? Or of a poisoner?