Bai Guo is accidentally selected by the system. As long as he completes the time travel mission, he can get a wish. However, Bai Guo, who has no ambition, has the motivation to complete the mission seriously because of his terminal illness. But what happens next is beyond his control. The chosen one? One in a million? Control the overall situation? It's simply Bai Guo's delusion. He is probably a wage earner under the system. But as the days of time travel increase day by day, Bai Guo grows from an ordinary passerby to a protagonist who rewrites history.