Mu Huainan was a decathlon champion on Earth in his previous life. He was proficient in all skills such as fighting, shooting, driving, and wilderness survival. However, he traveled to the Western fantasy world in an accident. Reborn as a useless magician, he discovered that he had a golden finger - the "omnipotent system" that could master any skill instantly. However, this former God of War on Earth is an idiot in life: he can't cook, wash clothes, and can't even tie his shoelaces well. In order to survive in this world of swords and magic, he must rely on all kinds of companions around him. But the trouble is, an intelligent villain with a superior IQ has targeted him, believing that Mu Huainan hides the secret of the ancient demon king. The memories of his past and present lives were intertwined, and Mu Huainan gradually discovered that his time travel was not an accident, but was inextricably linked to the Demon King from thousands of years ago.
