Climbing a Tower Which Even Regressors Couldn't Conquer

My girlfriend, who was drunk and lost her mind, suddenly said strange things. "Su-hyeok, I've regressed." "Regressed?" "Yes, I've come back in time." "Are you crazy?" "You are the only hope for humanity." And then I was taken to the tower... But it doesn't matter! Regressor? Tower? Trials? Whatever it is, It doesn't matter but what I know is I'll conquer this goddamn tower! (Source: Kakao Entertainment Corp., translated)