The Hostage by Susan Wiggs

Chicago, 1871

Deep within the quiet of the night, a city erupts into flames, and a spoiled heiress is soon whisked away.

Deborah Sinclair is a beautiful, accomplished young heiress with a staggering dowry. But her fortune does her no good when, one horrible night, Chicago is engulfed in flames.

Tom Silver will walk through fire to avenge a terrible injustice—and he may have to. But when he makes Deborah a pawn in his revenge, the heat of the inferno fades next to the attraction he feels for his captive. And the further he takes her from everything she's known, the stronger their passion grows, until it threatens to consume them both.