正要赶往伦敦完婚的凯莉（Margaret Lockwood）因雪崩被困在山下的小旅馆里，偶遇摄影记者康德（Michael Redgrave），两个人因小事发生争执，第二天大家各自赶路，却登上了同一列火车。
　　在车上凯莉与一名老妇人佛洛伊（Dame May Whitty）结伴，彼此照料。然而凯莉因头部被撞，恍惚中沉沉睡去，待她醒来，老妇人不见了。四处寻找佛洛伊，却不见她的踪影，凯莉只好报警。出乎意料的是同车厢的每个人都说没见过什么老妇人，陷入困惑的凯莉再次遇到康德。康德相信凯莉，也感到事有蹊跷，两人渐渐和好，一起展开了调查。

　　A clever fortune-hunter with a penchant for murder does in his elderly, supposedly rich, wife and manages to get away with it. After an investigation results in a decision of 'accidental death', our crafty killer discovers that his late wife's 'fortune' is not what he thought it was. Driven to find another unsuspecting spouse; he discovers that his new bride, a widow, is no fool. When she tells him that she intends to keep her accounts separate from his, he is driven to contemplate murder once again

一个聪明的寻宝者喜欢谋杀他年迈的、据说很富有的妻子，并设法逃脱了惩罚。在调查结果为“意外死亡”后，我们狡猾的杀手发现他已故妻子的“财富”并不像他想象的那样。他被迫寻找另一个毫无戒心的配偶；他发现他的新娘，一个寡妇，并不傻。当她告诉他，她打算将她的账户与他的账户分开时，他被迫再次考虑谋杀