Cleanup! Titan Junior High School (清掃！巨人中学校 Seisō! Kyojin Chūgakkō?) is the 4th episode of the 1st season and the 4th episode overall of the Attack on Titan: Junior High anime, produced by Production I.G.
Eren and the others are forced to join the Wall Cleanup Club since the Scout Regiment Club is an unapproved club. There, they are tasked with cleaning windows by Rico. Impressed by their work, she agrees to teach them how to use the club's secret equipment, the omni-directional mobility gear. Eren, however, fails the test because of an equipment failure. Hannes, the club's advisor, arrives to show him how it is done, but crashes into the Wall due to being drunk. This allows Rico to save face by blaming the broken equipment on Hannes. Two Titans then appear, and the club watches in horror as they vandalize the Wall. Rico explains that this is why the Wall Cleanup Club was originally founded. Outraged, Eren attacks the Titans, only to end up covered in paint.
Because of the unauthorization of the Attack Junior High Scout Regiment as a club, Eren, along with Mikasa, Jean, Conny, Sasha, and Armin trouble themselves into joining the Wall Cleanup Club instead. Striding to the clubhouse, Conny speaks up for his make-believe club of "Going-home" with Eren betting on it to be as secretive as the Scout Regiment itself. Although Armin conveys everything they are talking about in an optimistic way. Not upon his futon, strangely gains Eren's suspicion. Armin reveals the new renovation of his futon which is actually a mesh that holds up water to cool himself.
Rico Brzenska, the president of the Wall Cleanup Club, warmly welcomes the group into the association. Despite the fact that once the club consisted of a hundred members, Eren and the others do not like their treatment for they do basic cleaning duties and nothing else. Rico briefly attests that they are free to go to any other club, with an exception of human clubs, which are already full. Certain with the fear of being in a club with Titans, Eren and the rest reluctantly agree. With that said, Rico orders them their first task: clean all the windows.
Rather than wiping the glass, Eren mumbles to himself being a loser and envying the other students in more appropriate clubs. As some students pass by, dropping off sneers towards them, Jean nerves up claiming that he wants to be popular. He climbs to the window and jumps off as Eren and the rest remind him that they are in the third floor of the building, and the distance causes shocks sending through Jean upon landing. He is about to scamper, not until Rico spots him and zooms onto his direction, taking Jean down. Rico introduces them to the secret weapon of Wall Cleanup Club exclusively used in maintaining the Walls, the omni-directional mobility gear. Dazzled, both Eren and Jean thought of a lot of uses of the device in their own ways and end up quarreling in order for Rico to teach them. Affirming that the boys are idiots, she makes a deal that if they finish the task given to them then she claims to tutor them how to use the gear. Moments after, Rico whines about the group's hype of the gear up until she is greeted by a bright burst of light coming from the cleanliness of the windows. Rico bursts out in tears granting the promise she has once set.
Armin advises a worn out Eren to continue his practice for the gear tomorrow as he ignores him and proceeds to bang his head repeatedly in the process, slamming it onto the ground. On the other hand, Jean, Conny, and Sasha are having fun, flying with their gear in the air. Rico states that if Eren does not know how to use the gear himself, he would have to leave the club. Mikasa tells Eren to give up on his goal to eliminate Titans, but Eren refuses. She states that no matter his determination, he does not get to decide if he can stay in the club. Meanwhile, Armin comments out the defectiveness of the gear being the sole cause of Eren's failure. Rico denies the case, for the gear is skilfully made.
She then yields the past of the equipment and how the club was founded and assures them on a bet of eating spaghetti through her nose. Looking closely, Rico is startled to notice a busted spring on Eren's gear as Mikasa asks if there truly is a fault in the gear, frightening Rico. Within a sudden, a drunk Hannes comes to Eren's guide, introducing himself as the advisor of the cleanup club. He grabs the broken gear from Eren and demonstrates him how to use it, although Rico is freaking out about the mistake. Hannes goes in a flawless take off until the mechanism busts off and he crashes into Jean. Upon getting up from his fall, Hannes confronts Eren not to give up and his collapse is because he is drunk. Rico then keenly points out the broken gear to be the problem for covering up her entirely unreasonable suspicion.
The next day, Eren successfully balances on the gear, thinking to himself that Mikasa should stop treating him like a child. Everyone is happy for Eren, except for Mikasa, who believes Eren is happy because he can clean the Wall with her as company. Suddenly, Sasha senses a tremble from the ground as Rico hurriedly commands everybody to hide. A group of Titans come rushing and start to vandalize the Walls. Rico explains the lone reason the club was founded. She points out the club's purpose is to maintain the Walls against the mess the Titans make. Full of rage, Eren storms towards the Titans and attempts to attack them. Only for the gear to run out of gas and Eren to be covered up in red paint. The Titans make their escape and lastly, Eren vows to destroy every single one of them.