Chasing! Titan Junior High School

Tsuiseki! Kyojin Chūgakkō (追跡！巨人中学校) is the 2nd episode of the 1st season and the 2nd episode overall of the Attack on Titan: Junior High anime, produced by Production I.G.

Overview
Eren and Mikasa are sent to collect a club admission form from Armin, whom has secluded himself at home all winter for fear of the cold. On the way, a Titan attempts to steal their gifts of food, but is defeated by Levi, who then steals Armins's futon. In an attempt to recover the futon, Eren and his classmates track down the Junior High Scout Regiment, a secret, unapproved club. There they meet Eld, Oluo, Petra, and Gunther. Levi arrives with Armin's futon, which he had stolen in order to mend a tear it had developed, and accepts all of them into the club.

Trivia

 * The song Mr. Arlert is singing is Feuerroter Pfeil und Bogen, the first opening theme of the original Attack on Titan anime.