Isabel Dalhousie, philosopher and amateur solver of other people's problems, meets an old foe, Minty Auchterlonie, at a birthday party attended by their young children. Ambitious Minty, now the head of a small investment bank, is in trouble with her shareholders. Isabel becomes involved, and is drawn into a murky world of financial concealment.

Minty is not the only high-flier in Isabel's life; her niece Cat has just become engaged to a tightrope-walking stuntman. Isabel fears his next job - and the engagement - could end in disaster. Meanwhile, her own boyfriend Jamie has marriage in mind too . . .