Cheon Hwi, the Sword Demon, began wielding his sword to escape hunger and rose to the level of a supreme master. The Central Plains spiral into catastrophe with the arrival of the Heavenly Demon, the greatest warrior of all time and a veritable disaster for the martial arts community.

Cheon Hwi forms a deep bond with Dang So-wol, the Dukmuhou of the Sichuan Tang Clan, who was left alone after losing her entire clan to the Heavenly Demon, and joins her in her quest for revenge against the Heavenly Demon.

However, the tips of their swords fail to reach the Heavenly Demon, and they meet their deaths on the same day in the same place. If only they had had a little more talent. If only they had had a little more time.

If only they had mastered a slightly stronger martial art.

At the height of his regret, Cheon Hwi returns to the past twenty years.

Having quickly regained his original abilities, the "young" Cheon Hwi resolves to protect her this time for sure.

Thus, he seeks out Dang So-wol, who is making her debut in the martial arts world at nearly twenty years old, and kidnaps her.