Danganronpa: Kibou no Gakuen to Zetsubou no Koukousei The Animation

Makoto Naegi, a teenager with no remarkable talent, is surprised to learn that he has been accepted into Hope's Peak Private Academy: an elite school that gathers the best students from various fields. Despite believing his admission was just a fluke, Naegi is delighted to attend an institution known for ensuring success to those who graduate. Determined, he enters the front doors of the prestigious academy. However, after losing consciousness inside, Naegi wakes up in a seemingly abandoned classroom. Failing to comprehend how he got there, Naegi begins to explore, and to his surprise, finds his classmates assembled in the gym. While everyone is trying to figure out what happened, they are confronted by the school principal—Monokuma, a robotic teddy bear. The mysterious toy explains that the freshmen are trapped inside the school with only one means of escape—kill a classmate without being discovered. Tension fills the air as Naegi and his classmates realize that they are faced with two choices: participate in Monokuma's killing game, or reside together in the school for the rest of their lives.

Plot summary from MyAnimeList. Data and images via Jikan API.