"I won't let you live again." Facing the monumental task of unifying the martial arts world, the head of the Namgung family, 'Namgung Hyun-ho,' watches in horror as his beloved 'dog' annihilates his entire clan. In the moment he feels his neck being severed, he suddenly finds himself back seven years to when he first met that 'dog.' But things are unfolding differently this time around… On top of that, the 'dog,' 'Baek-gyeon,' returns completely wrecked, making his vow of revenge seem meaningless. Was it really you who killed me back then? Truths gradually cast shadows on everything that has been concealed. The past shifts little by little. A bizarre intertwining of the slain Hyun-ho and the slayer Baek-gyeon unfolds in a thrilling tale of revenge and action.