Dark ground trilogy

Robert wakes up naked and alone in a thick jungle. The last thing he remembers is being in a plane with his family, but there is no sign of a crash or survivors. Then he discovers the shocking truth--he is in the park near his house, but his familiar world has been transformed into an alien landscape. When he finds others in the same position, he enlists their help in getting back home. But the journey is more perilous than Robert could ever imagine....

Robert tries to get answers from Magee, the strange man he met on the airplane, and works with Tom and Emma to try to rescue Lorn and the others before winter arrives, while Lorn takes it upon herself to find answers and a way to escape her past, if not her present, captivity.