Arthur (Freddie Highmore) receives a distress call from Princess Selenia (Selena Gomez) and flies to her rescue, but Emperor Maltazard (Lou Reed) has a nefarious plan to ensnare the young hero.

Arthur becomes a champion to his beloved Princess Selenia as her people try to fight off the attack of the evil Emperor Maltazard. A great adventure that takes Arthur deep underground as he vows to help his new friends.