Beyond all Boundaries book 3 (Interdimensional Worlds)

As the story moves into the last book of the trilogy, we know that Chaldee’s kingdom has been destroyed, meaning she must seek a new homeland, but the search seems fruitless until, with the help of her Earthling friends, the search leads them into the wonders of a secret city, hidden deep underground. Meanwhile, in Sydney, Jake’s efforts to help Adele and her father end in tragedy, forcing Jake and Ben to reach out to Chaldee. At the same time Chaldee’s enemy, the Commander, has been captured by an army unit and taken back to Sydney. Their intent is to use him to find Chaldee, but he outwits them. Eventually, when the five Earthling friends are united, they are welcomed into the mystical city, and through the help of the masters of that city, Chaldee is offered a place of environmental perfection, thus they are led to the kingdom’s new home.