Newly crowned Queen Catrina settles into her new role as Camelot’s first lady. But as her troll nature is revealed, her power over Uther increases affecting the entire kingdom. When Catrina accuses Merlin of stealing, he is forced to sneak around the castle trying to find a way of revealing Catrina for who she really is without getting caught. But is Merlin’s magic powerful enough to break the troll’s spell?