"Time Repairer" Shen Yan can enter the folds of memory to repair the fragments to prevent them from turning into harmful "remembering ghosts", but he only has seven seconds of memory and will forget everything related to it after the mission is over. New partner Lin Ye can see "Yi Gui" and always helps Shen Yan get familiar with the process after he loses his memory, and still remembers his habits.
During a mission, Shen Yan triggered his own memory fragments and discovered that the scar on the wrist of the boy who saved him from the fire twenty years ago was the same as Lin Ye. As the mission progresses, they discover that all the memories to be repaired point to the same disappeared town, and Lin Ye's identity becomes increasingly suspicious. He knows Yigui's weaknesses and can complete difficult repairs on his own.
The largest Yigui appears and takes the form of a boy in the fire to reveal the truth: Lin Ye is the boy from back then, a "Yi Ling" pieced together by Shen Yan using his own memory fragments. Its existence is a violation of the rules of time, and Yigui wants to devour him and correct the rules. Shen Yan needs to choose between abiding by the rules and retaining the memory of the forest.
In the end, Shen Yan refused to repair his memory and told Lin Ye that he remembered him before his consciousness disappeared. Although cracks appeared in Lin Ye, he held back and said that he would remember all the time. At the end of the story, the disappeared Shen Yan used his last strength to leave complete memory fragments about them to Lin Ye, and new plants grew on the ruins of the town.
Concept: Memory and the meaning of existence