Time will not go back, but memory will be caught between reality and echo. They try to rewrite their destiny, but they don't know that they have already become a part of time. Ten years ago, a mysterious fire engulfed "Institute No. 10", Taking away Lu Xingchen's parents and brother, and sealing a truth that had been erased by the authorities. Ten years later, Lu Xingchen met the phantom of his brother who should not exist in the "Diaodian Forest" of an abandoned subway station. What was even more bizarre was that the bronze pocket watch he held in his hand was exactly the same as his own. After an accidental time travel, he and his classmate Lin Wan fell into the "echo layer" - a parallel time and space composed of collective memories. There, they witnessed the end of the war in 1945, but due to Lin Wan's mistake, the existence of the hero was accidentally erased, causing the time anchor to collapse, causing the real world to become distorted and chaotic. After returning to reality, they found that the world was no longer familiar: the flow of time was disordered, cracks appeared in memory, and those who should have been forgotten were returning from the gaps in time. In order to restore time and find their missing relatives, Lu Xingchen and Lin Wan embarked on a journey to find the "key" - a key made of memory and sacrifice, hidden in the ruins of Research Institute No. 10, Hidden in the riddles left by their father, and hidden in the past that they dare not look directly at. At the junction of mirror and reality, on the edge of memory and illusion, they will face a cruel truth: some things cannot be changed, and some people are destined to disappear. But the true bond will not dissipate over time
