The orphans Niklas and Sophie grow up sheltered in the Wittichen monastery. They have no idea that an old secret lies dormant behind the thick walls of the monastery. However, rumors soon bring the order into disrepute. A miracle staged by the prelates is meant to attract pilgrims. The children's curiosity is piqued, and the deeper they dive in, the more they must realize that they themselves are part of the conspiracy. In their search for their true identity, dark forces are unleashed, threatening to drown the children in their swamp.