The anime follows the story of Yukiteru Amano, an introverted year old boy, who writes about his awkward and uneventful life in his cellphone diary. However, everything changes when Yukiteru has been thrust into a battle royale-like scenario and one of the few allies he has is Yuno, which some may consider being the mascot of " yanderes ". Yanderes are character tropes, primarily females, whose seemingly innocent infatuation with someone turns into an aggressive, insane obsession. They often try to hide their sick fixation with cute behavior, but their true hostile and sometimes homicidal nature always comes out. Yuno Gasai is a master manipulator as she balances between being adorable and psychotic to Yukiteru.