Aldia, the strongest Knight of the Kingdom and the key figure in ending the war between the Kingdom of Reshufelt and the Vulcan Empire. Though he became a Hero, Aldia was executed on false charges. He died with deep Regret in his heart for failing to protect the Imperial Princess Waltraune, who had once saved his life... However, having regressed to the world on the eve of the war six years ago, he swears loyalty to the Princess and becomes a Knight of the Empire to clear his regrets. Everything is for the sake of rebelling against destiny——.