Ansatsu Kyoushitsu

Synopsis

Karasuma, Irina, and a team of fifteen students scale up a mountainside to sneak into the hotel undetected. With the first floor heavily guarded, Irina uses her seduction and piano skills to distract the guards so the others can reach the next floor. On the third floor, the group come across their first opponent, Smog, the one who poisoned everyone with the virus, who hits Karasuma with a paralysis gas, but still gets knocked out by him. Finding their next opponent, Grip, on the fifth floor, Karma, having learnt from his failures in the exams, steps up to fight against him.

(Source: Wikipedia)