Li Jingyuan, Crown Prince of the Great Heng Dynasty, loses his power after the deaths of his mother, the empress, and his maternal uncle. He is targeted by the Eighth Prince, Li Zhe, who orders the eunuch Liu Huan to murder him. After traveling through time and awakening the Great Tyrant System, Li Jingyuan summons the Shadow Assassins to kill Liu Huan and uncover the conspiracy. He obtains Dian Wei and the Tiger Guard Army, publicly humiliates Li Zhe, and cleverly secures the establishment of the Eastern Palace's Six Guards. Investigating the state's finances and grain supplies, he exposes the Wang family's grain business, which is colluding with Li Zhe, and confiscates its assets to gather evidence. Along the way, he survives an assassination attempt by the Taiqiu Sect, destroys the sect, and builds a monument of enemy corpses. He gains Deng Tai'a and Shen Wansan as well. Upon returning to the capital, he overcomes Lü Xingchao's obstruction, foils Li Bibo's scheme in the library, and punishes the second son of Prince Kangyi for injuring others, ultimately winning Prince Kangyi's admiration and submission.