"FarWorld book 2: Land Keep" by J Scott Savage

If you aren't familiar with J Scott Savage's first FarWorld book, WaterKeep you'll want to check it out first. The basic story is that we have two teens, both from alternate 'worlds' that essentially use the same space. Farworld is a magical place where everyone has magical abilities. That is, everyone except Kyja, who has none. Marcus, here in our reality, however, has found he does have certain abilities, despite the fact that he is consigned to a wheelchair and lives in an orphanage. When FarWorld is threatened, Marcus is pulled back there to help get the Elementals to help fix things. There are four sets of Elementals. In this book, they try to find the Land Elementals. The blurb follows.

Four mythical Elementals— Water, Land, Air, and Fire— have the power to save two worlds, Earth and Farworld, from a common enemy: the Dark Circle. In book one, Water Keep, a portal has been opened between the two worlds, allowing Marcus, from Earth, and Kyja, from Farworld, to combine their unique gifts and begin their epic quest to find the Elementals.

In book two, Land Keep, Marcus and Kyja travel with Cascade, a Water Elemental, toward Land Keep, the home of the powerful and wise Land Elementals. However, their journey may end before it even begins. Land Keep is empty, deserted for at least a thousand years, and the rumor is that the creatures who once controlled all land magic are extinct. Marcus and Kyja's only hope seems to lie in finding the Augur Well, a legendary Oracle protected by subtle traps and mind-bending trials. To succeed in their quest, Marcus and Kyja must also avoid the Keepers of the Balance, an order dedicated to redistributing magic to the rich and powerful. And they must travel far underground, where Cascade is unable to follow and where they will be unable to leap to the safety of Earth.

As the Dark Circle closes around them, Marcus and Kyja are faced with the temptation of what they desire most. Sacrifices must be made, and not everyone will survive unscathed.

The FarWorld books are considered middle-grade books, but appeal to much older readers as well (including yours truly). They are now available at DeseretBook.com, and should be seen in some stores already, with many more to come.