Tainted World: (Tainted, #4)

 After being sent to a confusing and terrifying new world, Ariella promises herself that she will find a way to get back home. No matter what it takes. After being poisoned, attacked, and lost deep in the forest, the group knows that if they stay in Nargo, none of them will be alive much longer.

Just as things are starting to look up with the help of a new friend, and they think they might have found a lead, Daymon goes missing. When they track him, the tracking spell tells them that Daymon has somehow managed to get back to earth. Not only that, he's human, but how? With a time ratio of ten Earth years for ever one Nargo year that passes, they don't have time to waste. If it takes them a year to get home, a decade will have passed on earth. 

Unbeknownst to anyone, something dark is brewing back home on earth. Old ways are being mixed with new ways. Someone is up to something that threatens all that the group has tried so desperately to prevent. Magic is back, in fact, it never left.