Changeling (The Oddmire #1)

Magic is fading from the Wild Wood. To renew it, goblins must perform an ancient ritual involving the rarest of their kind—a newborn changeling. But when the fateful night arrives to trade a human baby for a goblin one, something goes terribly wrong. After laying the changeling in a human infant’s crib, the goblin Kull is briefly distracted from his task. By the time he turns back, the changeling has already perfectly mimicked the human child. Too perfectly: Kull cannot tell them apart. Not knowing which to bring back, he leaves both babies behind.

Tinn and Cole are raised as human twins, neither knowing what secrets may be buried deep inside one of them. Then when they are twelve years old, a mysterious message arrives, calling the brothers to be heroes and protectors of magic. The boys must leave behind their sleepy town of Endsborough and risk their lives in the Wild Wood, crossing the perilous Oddmire swamp and journeying through the Deep Dark to reach the goblin horde and discover who they truly are.