The "liminal corridor" is an infinite mission space that exists in the gap between reality. Each time it is opened, "candidates" from different time and space will be randomly selected and forced to enter a different world that combines history, mythology, and future technology to complete the mission. Candidates who fail the mission will be "erased from existence" by the corridor. Only by accumulating enough "threshold points" can they redeem their qualifications for escape or their wishes in the real world. Deep in the corridor, there seems to be a hidden "administrator" who controls the rules, as well as the ultimate secret of the candidate's selection.
Concept: The ultimate mystery