Man about town and First Class cricketer A.J. Raffles keeps himself solvent with daring robberies. Meeting Gwen from his schooldays and falling in love all over again, he spends the weekend with her parents, Lord and Lady Melrose. A necklace presents an irresistible temptation, but also in attendance is Scotland Yard's finest, finally on the trail.

A car accident traps two men inside a car near the water. With the tide coming in, they discuss the circumstances that led up to the accident.

马洛（迪克·鲍威尔 Dick Powell 饰）是一名独来独往的私家侦探，某日，马里特（Douglas Walton 饰）找到了马洛聘他当自己的保镖，结果马洛却莫名其妙的挨了一顿打。之后，一个叫安（安妮·雪莉 Anne Shirley 饰）的女孩现身，她告诉马洛，他所遭遇的一切和她的继母格雷尔夫人及其所拥有的翡翠有着千丝万缕的关联。对翡翠深感好奇的马洛决定将这一连串的事件调查个水落石出。
在安的协助下，马洛对事件的全貌渐渐的有了了解，而隐藏在背后的，是安的父亲（迈尔斯·曼德 Miles Mander 饰）。不仅如此，不久之前，马洛受雇寻找一个名叫维尔马的女子的下落，这名女子竟然也被牵连进了翡翠的案件之中。