Imagine a girl of twenty, whose rich foster father is lying ill in the hospital following a heart attack. Another man turns up claiming to be her real father. Although Nora Sanderson doesn't know whether to believe him or not, fear and the fascination of horror lure into a dangerous relationship with him.
The oddities of the situation multiply rapidly (for one thing, the stranger's appearance is variable, and so is his voice); likewise the dangers, especially after Nora's fiance and a worker from the adoption agency come to her rescue, or try.
The story of flight and pursuit and breath-taking escape ranges from a ratty Greenwich Village rooming house to the Sanderson's very much more elegant apartment uptown. The eminently satisfactory conclusion comes in an old Connecticut country house- the hero on this occasion being a black and white tomcat named Toby, who distinguishes himself - even among the distinguished gallery of Lockridge cats - by giving the police an indispensable assist at the last minute.