Fused Legacy of Magic Book 6 - Lindsay Buroker

Matti Puletasi finally has the chance to confront those who kidnapped her parents, and she'll do it with Sarrlevi, the elf assassin she's come to love, at her side.
But now that they know great and powerful dragons are involved with the organization, they may be in over their heads. Their opponents aren't just kidnappers. They're on the verge of enacting a plan they've been working on for decades, one that could cut off Earth from the rest of the Cosmic Realms and bring humanity to its knees.
All Matti ever wanted was to find her parents, but it may be up to her to save the world.