理查德是一名飞行员，退伍后，他在一家酒吧打工，认识了同事芭芭拉（安娜·玛西 Anna Massey 饰）并与之相爱。性格粗暴的理查德同老板发生口角后被开除，身无分文的的只得投奔前妻布伦达（Barbara Leigh-Hunt 饰）。布伦达经营着一家婚姻介绍所，她友善的接待了理查德并偷偷的在他口袋里塞了一些钱。没想到几天后，布伦达在介绍所中被她与理查德共同的朋友鲍伯（巴里·福斯特 Barry Foster 饰）玷污并用领带勒死，原来鲍伯就是伦敦臭名昭著的领带勒杀狂魔。

Childhood friends Tommy and Tuppence meet in London after having served in World War I. Recently "demobed", short of money, and with no job prospects, they decide to bee adventurers for hire. Soon, they are employed by the British Government to locate a secret treaty signed before the war.