The Fractured City by Morgan Moreau and Kate Jenkins

She might be the queen, but mounting pressure from the old guard prevents Collette from making real change in Coralia. Following the death of her father, Collette dreams of peace and prosperity for her people. She wants to stop the Merscales trade and grow the economy through international cooperation. The nobility wants to maintain the status quo. ​ When an important visit from the Nereid emissary is overshadowed by the brutal murder of Wrenn Almeida, Collette finds herself accused of murder by Wrenn's sister, Rhoslyn. As tensions rise between herself, her half-brother Zephraim, and Rhoslyn’s supporters, the queen finds that her only choice is to flee the kingdom. Her allies—a trio of mercenaries, her aging guard captain, and her half-human lover—must stop at nothing to protect her.