During the Joseon Dynasty, Ryung acted as a hooligan in the marketplace by day but at night he was a thief who robbed corrupted government officials to give to the poor.
Human/were-fox half-breed Choi Kang Chi discovers the truth about his origins and searches for the mystical Gu Family Book, which holds the secret to becoming fully human.
When the queen-to-be of medieval Korea is badly wounded, Captain Choi Young uses a wormhole to "heaven," which is actually 21st-century South Korea, to bring back the spoiled Dr. Yoo Eun-Soo who becomes a pawn in a game of human chess.