Durarara!! - Season 0 Episode 2 World at Peace

Yuuhei hosts a show searching for the loveliest couple in Ikebukuro, the winner of which gets to appear in one of his movies. As Mikado and Anri go to the movies together, hoping to clear everything up between them, they are interviewed by Yuuhei. A guy with a knife tries to attack Yuuhei, but he is stopped by Shizuo, who is also being hounded by Izaya's sisters wanting to meet Yuuhei. Shizuo then encounters Izaya, who arranged for the attack, and enters a huge fight with him which escalates throughout Ikebukuro, prompting Celty to move into action. As the fighting escalates, several smaller fights break out, forcing Celty to use her powers to stop everyone. This is Episode 25 of Season 1.