On sick leave from Scotland Yard, Inspector Alan Grant is planning a quiet holiday with an old school chum to recover from overwork and mental fatigue. Traveling on the night train to Scotland, however, Grant stumbles upon a dead man and a cryptic poem about "the stones that walk" and "the singing sand", which send him off on a fascinating search into the verse's meaning and the identity of the deceased. Despite his doctor's orders, Grant needs just this sort of casual inquiry to quiet his jangling nerves. But what begins as a leisurely pastime eventually turns into a full-blown investigation that leads Grant to discover not only the key to the poem but the truth about a most diabolical murder.

约瑟芬·铁伊，1897年生于苏格兰因弗内斯，就读于当地的皇家学院。之后，在伯明翰的安斯地物理训练学院接受三年训练，然后开始物理训练讲师的生涯。后来，她辞去教职照顾她住在洛克耐斯的父亲，并开始写作。

这位英籍女作家，是20世纪30年代以来，推理史最辉煌的第二黄金期三大女杰之一，也是其中最特立独行的一位。和她齐名的阿加莎·克里斯蒂、多萝西·榭尔斯都是大产量、行销惊人的作家，铁伊却穷尽一生之力只写了八部推理小说，八部水准齐一的好小说——是推理史上极少数一生没有任何失败作品的大师。