The train that is taking the students of Conexo through the mountains on their Winter Break derails as it’s going through a tunnel. Five students in their final year, Eva, Noel, Sabina, Gabi and Sam, are the only survivors. But no one comes to rescue them, and the snowy mountains turn into a labyrinth where inexplicable things start to happen. Fighting the elements and their own frictions, they manage to make it home, where it seems no one has missed them. Because when they get to Conexo they find five identical teens have taken their place... Why have they been duplicated? What did really happen in that mountain tunnel? Why are the past and the future now weaving together inside their heads? They have to solve the mystery, or the world is going to collapse. And it will all be their fault.