Camelot's legendary tournament has only one rule: there are no rules. As the mythic city fills with terrifying warriors, they are joined by Gilli (Harry Melling) who despite his small stature has victory in his sights and he has a secret weapon to help him - magic. As Gilli begins to realise the full potential of his powers, Merlin finds himself torn. Not only is his new friend putting his own life in danger, but his actions threaten to rip apart the very fabric of Camelot itself. Can Merlin make Gilli see sense before its too late?