Su Ming, originally the world's number one assassin, saved hundreds of millions of his human compatriots and was revered as one of the ten strongest experts of the Dragon Country. However, he was framed and killed by his lover and his brother, dying filled with hatred and buried in the S-Rank Dungeon, the Death Den. Unexpectedly, he was actually reborn, returning to his high school days on the very day of the Awakening Ceremony. He even obtained a Mythical-grade talent!