Time is not a river. It's a tree.
Each branch represents a different choice, and each branch leads to a new reality. But somewhere out of sight, a group of men were chopping down the tree—cutting off all the branches that didn't fit the bill, leaving only the one they wanted.
This group of people built the "Past" - a train that can travel between the branches of the Tree of Time. Every passenger who boards the bus is a data mine. Every time traveler who tries to change history will be harvested.
And Lin Fei - an ordinary person who once inspected bolts on the railway tracks - happened to be the one they couldn't harvest.
Because he can not only see the future, but also replace the future with another outcome. For before his father was imprisoned into eternity, he had sown seeds all over the tree.
Now, the seeds are about to germinate.