Everlost (The Skinjacker Trilogy)

IT BEGINS WITH AN ACCIDENT. Nick and Allie don't survive the crash, and now their souls are stuck halfway between life and death in a sort of limbo called Everlost. It's a magical yet dangerous place, where bands of lost souls run wild and anyone who stands in the same spot too long sinks to the center of the Earth. Frightened and determined, Nick and Allie aren't ready to rest in peace just yet. They want their lives back, and their search for a way home will take them deep into the uncharted areas of Everlost. But the longer they stay, the more they forget about their pasts. And if all memory of home is lost, they may never escape this strange, terrible world.