The protagonist mistakenly enters the "Seven-Day Market City" - an abandoned ancient city shrouded in thick fog and where time has stagnated. "Seven Days" is used as a reincarnation cycle here. Every midnight on the seventh day, all participants who have not collected the "Twenty-Four Solar Seals" will be cleared by the "fog shadow" of the market city. They will lose all their memories in the early morning of the eighth day and be resurrected, falling into an endless cycle.
Time stands still outside the city, and time passes normally inside. There are dilapidated ancient houses, deserted streets and alleys, as well as "aboriginals" who have been eroded by the "fog shadow" and become mentally disturbed (participants who have not escaped in the past and have lost their self-awareness). Core metaphor: The market city is an abandoned place for ancient solar terms sacrifices, the participants are the "sacrifice", the cycle is the unfinished sacrificial ritual, and the solar term seal is the key to breaking the ritual.
