Du Tutu, a teenage boy from Pig Butt Village, was born with an unlucky constitution and is illiterate. On his deathbed, his grandfather entrusts him with a bronze waist token, telling him to go to the Qingxuan Sect to find his senior brother Hong Yang. Du Tutu holds the Body Tempering Formula upside down and practices it anyway, accidentally mastering the Iron Head Technique and the Divine Mobility Step. Relying on eating brain-eating beasts and demon king meat, he constantly grows stronger. At the sect grand competition, he does a headfirst dive and knocks out Ye Tian, the chief disciple of Thunder Peak, and is mistaken for the "sect foundation". In the Ten Thousand Beasts Valley, he blends into the beast herd, plots the deaths of the brain-eating beast clan and demon kings, and strikes terror into the hearts of demonic beasts. Eventually, along with his senior brother and senior sister, he investigates abnormal disturbances, discovers a spirit stone vein, and cooperates with a tiger demon to contend for the position of demon god.