Chantarelle (The five stones trilogy, 2)

In Book Two of The Five Stones Trilogy, Chase, determined to fulfill his promise to find the unifying Fifth Stone, finds the elusive Captain Nate and brings him back to the island of Ayda, where one realm is burning and two others are under siege from Dankar's dark forces of Exor. Meanwhile, Knox and Evelyn must trust a mysterious guide to help them find a way back, though each has their own personal struggle to overcome. All three children must decide if they can put their own needs―and fears―aside to save their friends and family.