During a non-stop flight to London, a valuable necklace is stolen and the courier hired to guard the necklace is poisoned. One of the passengers is Jessica Fletcher (Angela Lansbury), who of course offers her services to Scotland Yard as they try to retrieve the gems and catch the killer. Among the main characters in this melodrama are a famous actress, a taciturn former police officer, and a furtive-looking tourist couple. ~ Hal Erickson, All Movie Guide