​A year has passed since the Labyrinth was killed, but it seems Sieg still hasn't been able to take that next step in his relationship with Mariela. Far from it, he ends up upsetting her, and she runs away from home with the Black Iron Freight Corps! While traveling through the Fell Forest, Mariela's group encounters a mysterious shrine in a gloomy bog. After passing through the structure's doorway, Mariela awakens in a tower that appears to be underwater. She and her comrades will have to unravel the mystery of this place if they hope to get home. Could this fantastical realm have something to do with Mariela's missing master?