Magic and Goldfire (The Middenvale Saga Book 1) by Clare Rushing

When the world shatters, new heroes rise. Vesunna Padsva is a legendary knight with her own ballad sung by tone-deaf bards across the land. She tolerates the fame, but craves an escape away from guard duty and starry eyed townsfolk. When the high king announces a diplomatic mission to an isolated kingdom in the north, she eagerly volunteers. Unfortunately, the trip quickly turns into a nightmare. Hagol's cold climate is miserable compared to Sul Galen's year-round warmth. The people are simple, the king is incompetent, and diplomacy is not her strong suit. She's ready to accept failure when a familiar adversary arrives and things take a deadly turn. Sunny must team up with some unexpected allies on a quest to stop corrupt leaders from destroying her home--and save a forgotten magical land. Silver Muir has endured a lifetime of cruelty from the superstitious people of Hagol. She's worked hard to gain their trust by serving as apprentice to the royal physician, and has built a pleasant life for herself at Castle Dúnbright. But the rumors about her mythical, frost-bitten appearance may not be entirely off the mark. When a knight from Sul Galen arrives with an interesting offer, Silver begins a journey that will call into question everything she once believed about her heritage and her place in the world. She will have to decide whether to honor her healer's oath...or embrace her newfound power.