The instant of a car accident, Shen Qing signs an unregistered demon-hunting contract with the Reception Bureau. Without a master to guide him, he abruptly steps onto the path of hunting demons. When attacked by a parasitic demon, college classmate Chen Ye steps in to save him. Shen Qing follows Chen Ye to apprentice under Elder Wen for cultivation. In a life-or-death battle, Shen Qing detonates the contract's origin, leap-ranking to slay a rat demon, and his heaven-shaking power attracts prying eyes from various factions. When their cultivation reaches the third tier, the two use a passage to rush to the Demon Realm for trials. The demon race splits into main-war and peace factions; the main-war faction's Yazi, aiming to break through to the tenth-tier demon king, leads a massive army to besiege Nine-Tails City. As the fires of war ignite, Shen Qing and Chen Ye receive orders in times of crisis, guarding the city amidst the chaotic world and uncovering the deep-hidden secrets of the nameless contract.