The Commander and the Den A Saan Rautu by Michelle Franklin

In a desperate attempt to save her homeland, one commander makes an alliance that will change her life and her kingdom forever.

When Frewyn's last line of defense falls, Boudicca MacDaede, leader of the Frewyn armed forces, enlists the assistance of Den Asaan Rautu, one of the Haanta giants from the islands to the far north. After winning a war, spending a year fighting by her side, Rautu is called back to his people but finds it impossible to leave without the woman he has come to love. Now he must find a way to make her his mate while fending off an impending attack against his people that threatens to break them apart forever.