Book: Defend the Dawn by Brigid Kemmerer

To save their kingdom, they must embark on a dangerous journey... The kingdom of Kandala narrowly avoided catastrophe, but the embers of revolution still simmer. While King Harristan seeks a new way to lead, Tessa and Prince Corrick attempt to foster unity between rebels and royals. But the consuls who control the Moonflower will not back down, and Corrick realizes he must find a new source for the lifesaving Elixir. When an emissary from the neighboring kingdom of Ostriary arrives with an intriguing offer, Tessa and Corrick set out on an uncertain journey as they attempt to mend their own fractured relationship. This could be their only chance to keep the peace and bring relief to the people of Kandala, but danger strikes during the journey to Ostriary, and no one is who they seemed to be...