The son of the Duke and Duchess of Avon, the Marquis of Vidal is known as Devil's Cub not only for the excesses of his father but for his own wild habits.

As he is paying court to a girl of the bourgeoisie, Sophia Challoner, he also participates in a rather impromptu duel, the outcome of which forces him to leave the country.

But she has not yet obtained the measure of the Marquis's personality, for in the grip of fury he takes Mary off with him instead, and only when they are in France and it is too late for either to turn back does he realise that by abducting a respectable girl he has compromised her and is obliged to offer her marriage.

However, Mary refuses Vidal because she believes he is making the offer from guilt and as she has fallen in love with him she finds this intolerable.

Vidal pursues, and ultimately realizes he loves her, persuading her to marry him — in spite of Avon's dry observation that she could do better.