Isaiah's Daughter by Mesu Andrews and published by Waterbrook.
Ishma, a captive orphan, is as desolate as her name until she's released to the royal prophet Isaiah. Her lively spirit wins Prince Hezekiah's favor, a boy determined to rebuild the kingdom his father has nearly destroyed. Isaiah adopts Ishma, giving her a new name--Zibah, delight of the Lord--thereby ensuring her royal pedigree.
When the king dies, Zibah marries Hezekiah, but discovers even a queen feels like a captive when years of disappointment batter her heart. Zibah is still childless when the Assyrian army besieges Jerusalem, and Hezekiah is stricken with a fatal illness. She turns to the only One who can give life, deliver a nation, and heal her husband. Only Yahweh destroys an army without weapons. Only Yahweh heals a dying man in three days. And only Yahweh gives an orphan queen the son her heart desires.