Knight’s Fire by SJ Himes

Stories tell of great fire-breathing beasts large as castles, fierce and deadly, capable of magicks that no human can match. The Kingdom of Kentaine once allied itself with the dragons of old, but eventually, the dragons were lost to time and fell into legend.
Sir Gawain, First Knight of the Realm, is tasked by his older sister the Queen to travel to the edges fo their kingdom, where a beast is flaming villagers and has the locals ready to form a mob and hunt it down themselves. His mission is to find the dragon, stop the violence, and do what he needs to maintain the peace.
His journey puts him in the heart of a confrontation with the dragon, but instead of saving the villagers, it is the dragon that needs rescuing. Zephyr, a fire dragon and an escaped slave, needs protection, time to heal, and a chance at a life full of hope.
Gawain can do no less than offer his sword, his shield, and his heart. Evil is hunting Zephyr, and it will not stop until it has reclaimed its prize.
Beyond the legends lies the truth, and love, like fire, consumes everything it touches.