At the beginning and end of the book are "Leaves from Leah's Diary": William Kerby, a travelling portrait-painter, is in danger of losing his sight, and is required by his doctor to cease painting for a while.
They come near Glenwith Grange; Garthwaite knows Miss Ida Welwyn, a middle-aged woman who lives there, and they visit the house.
The married life of the Baron and Rosamond at Glenwith Grange is peaceful; however when a French provincial newspaper, which he receives regularly, fails to arrive one day his mood changes, and he leaves to make enquiries.
The French police have ascertained that this supposed imposter is genuine, and that Rosamond's husband is probably Monbrun, a fraudster who resembles Franval.
The identity of Rosamond's husband is proved soon afterwards: he returns and, while asleep, the French agent finds the branded mark that Monbrun was given when he was a convict.