Six "Gap Holders" were involved in the Zero Subway Loop. They either lost their memory or lost their perception, and they were shocked every step of the way through the strange levels such as the Taste Maze, Time Corridor, and Echo Town. Every stop is a reminder of the past, and every rule points to the accident that was deliberately buried seven years ago.
When the rusty train carried broken memories to the end, they discovered that the loop line was never a prison, but the only way for the forgotten to repent and for the survivors to dare to remember. And what they hold in their hands is never a gap, but the last piece of the puzzle to piece together the truth.
