Sand is a blacksmith apprentice who wakes up, alone, in a ruined castle, with no memory of how he got there or why. . . but the thorny brimbles that grow on the walls of the castle prevent him from leaving. Doing what he knows, he lights up the castle's forge to mend what he needs. But these things are working even better than they did before. . . is there magic involved?
Sand finds the castle's lost heir, and the two work together to uncover the secrets behind the castle's mysteries.