In a dystopian world torn by apocalypse and class divide, where people live underground, Greta's life mission is to become a Guardian... a powerful soldier in charge of protecting the 'God of Spring', the legendary king. Alongside her fellow soldier Elias, they'll embark in a quest to repel the attacks of the monstrous Outsiders and fulfill the king's prophecy: reclaim their land on the Earth' surface. But perhaps their mission isn’t all that it seems…