Summary from GoodReads: Olivia Grace has secrets that could destroy her. One of the greatest of these is the Earl of Gracechurch, who married and divorced her five years earlier. Abandoned and disgraced, Grace has survived those years at the edge of respectability. Then she stumbles over Jack on the battlefield of Waterloo, and he becomes an even more dangerous secret. For not only is he unconscious, he is clad in an enemy uniform.
But worse, when Jack finally wakes in Olivia's care, he can't remember how he came to be on a battlefield in Belgium. In fact, he can remember nothing of the last five years. He thinks he and Olivia are still blissfully together. To keep him from being hanged for a traitor, Olivia must pretend she and Jack are still married.
To unearth the real traitors, Olivia and Jack must unravel the truth hidden within his faulty memory. To save themselves and the friends who have given them sanctuary, they must stand against their enemies, even as they both keep their secrets.
In the end, can they risk everything to help Jack recover his lost memories, even though the truth may destroy them both?