Due to a Heavenly Tribulation, Zhang Han crossed back to the Earth from the cultivation world.
He crossed back to the date which changed his life - that rackless car race, that day, he was seriously injured in the accident, lost both arms, and then struggled to survive for 5 years eventually chose to jump off a cliff to commit suicide. In the falling, he crossed into the world of the cultivation world. After 500 years of cultivation, he finally reached the final Heavenly Tribulation, but coincidentally he crossed back to the car race day. Was this the necessary way to pass the tribulation, or was it a temporal disorder that caused him to go back in time?