Still reeling from the events in The Wizard's Apprentice, Lucas and his family retreat to live with his grandparents, King Navor's parents, while their home is rebuilt. When Gertrude comes to visit, Audrina realizes she needs to tell her grandparents about falling in love with her childhood friend. This, unfortunately, proves a challenge. With Lucas in turmoil, and Gertrude doubting the princess' love for her, the two team up and run away.
While their loved ones search for them, not knowing whether they're alive or dead, a storm maroons the runaways on a mysterious island. There, Lucas finds acceptance that he never thought he had at home. Meanwhile, Gertrude falls deep into a mystery that could topple a civilization.
Both must struggle with the new, strange land and, having landed there, whether they could ever go home.