Prisoners of Hope by Robin Hardy
Under Ares� command, Lystra has successfully defended her capital from invasion by a Qarqarian usurper who wants the legitimate heir, whom Ares is sheltering, dead. But this defense has come at the heartbreaking cost of many casualties among Ares� youngest soldiers.
In apparent gratitude, the ruler of neighboring Calle Valley invites Ares to inspect the ships confiscated from the enemy, now harbored at Prie Mer. So Ares accepts, bringing his young wife Nicole, a native of Prie Mer.
Once there, they discover that their host intends to keep them prisoners, for if he can do away with Ares, then that will end the line of Roman. But Ares and Nicole are harboring their own secret hope, based on a promise thousands of years old.
The Latter Annals of Lystra begins with Nicole of Prie Mer and continues in Ares of Westford and Prisoners of Hope. The next book in the series is Road of Vanishing.