Foul Play! An Old Examiner Grins! - S1.E2

Mumei is confined in a classroom full of traps. Trying to escape along with his comrades, they set off the traps and are sent to another world. A strange old man was waiting there. Mumei's classmates exhaust themselves without skills going up against an enemy that gets stronger the more he drinks. A sense of foreboding reaches the bewildered Mumei.