Ansatsu Kyoushitsu

Synopsis

Irina is greeted by her former master, retired assassin Lovro, who thinks she should give up as she has no chance of killing Koro-sensei. Hoping to prove him wrong, Koro-sensei proposes a match between Irina and Lovro to see who will be the first to "kill" Karasuma, offering Karasuma his own incentive should neither win. Despite Lovro's doubts after he fails to kill Karasuma himself, Irina manages to use what she's learned targeting Koro-sensei to get close, with Karasuma accepting defeat at her hands and Lovro acknowledging her efforts. Later, Nagisa, Karma, and Ritsu accompany Koro-sensei on a mach speed trip to Hawaii to watch the premiere of a new movie, getting a lecture along the way and learning a lot more about Koro-sensei's point of view. On their way back, a man in a while cloak observes alongside a boy, the second transfer student who claims to be Koro-sensei's brother.

(Source: Wikipedia)