"Principal for a Day" is the first segment of the twenty-sixth episode of Recess.
T.J. is made principal for a day, and the students are afraid that the power will change him.
The episode begins at recess where Menlo is taking the last entries for the Principal for a Day Contest, and Randall hands him a whole box full of them. Meanwhile, the fourth graders are playing kickball against the fifth graders and T.J. is up first, and they use Gretchen's new experimental giant metal shoe which gives them a home run. But it also breaks Principal Prickly's office window, getting him caught by Miss Finster and sent to Principal Prickly's office, where Principal Prickly makes him fill out an incident report and dismisses him afterward. After T.J. leaves, Miss Finster believes that T.J. would make a good candidate for Principal for a Day, but Principal Prickly thinks that she has gone crazy, because T.J. broke his window. Miss Finster then recalls that Menlo was worse than T.J. before he was "randomly chosen" for Principal for a Day, and Principal Prickly recalls that his behavior improved dramatically after that. Then he and Finster envision how a day between him and T.J. would change him too. Prickly then worries about him not being picked, and Finster told him that she'll see to it that he is picked. At the assembly, Miss Grotke announces T.J. as the winner just as Randall was about to accept the honor, much to his disappointment, and everyone cheers.
The next day, T.J. arrives at school with a crowd of kids waiting to greet him and he goes into Principal Prickly's office and makes the morning announcements with kid-friendly flavor, including all-day recess. Principal Prickly then commends T.J. on his excellent leadership skills, but then Miss Lemon tells them that a student was caught breaking one of T.J.'s rules. T.J. says that he'd just overlook it, but then Principal Prickly changes his opinion on the matter. T.J., not wanting Principal Prickly to doubt his leadership skills, decides to tell Miss Lemon to send him in, and the offender is none other than T.J.'s rival, Lawson. Lawson comes in assuming he'd get a reward for breaking T.J.'s rule of no sharing gum, but he instead receives a detention and is dismissed by T.J.. After Lawson left, T.J. fell silent, and Principal Prickly, concerned, told him about the first time he had to give a detention, but T.J. said he liked giving a detention. Then Principal Prickly praised T.J. for his leadership skills, and showed him his secret mini-golf game under the rug of his office and let him play on it. However, after he was distracted while making his putt, Principal Prickly said that the students should be back in class so he can focus more, and T.J. agrees. He then makes another announcement on the PA, telling everyone that recess is now over by sending the students to go back to class, and Principal Prickly praises T.J. for his move.
Afterwards, he tells T.J. that if he wants to be a good principal, he will need to change his image because the respect is measured by the price of a one man's suit, and he shows T.J. his wardrobe of suits, which T.J. loves very much.
So, later at lunch, T.J. makes an announcement rescinding all of his earlier rules and replaces them with new ones, and says that any violation of those rules will carry severe punishment. After that, he and Principal Prickly are receiving a massage until T.J. gets a page from Miss Lemon telling him they caught a sixth-grader running in the hall. He confronts the kid, and forces him to sign a form to be put in the Prickly Files, but as he does, T.J. sees himself in the kid. After Principal Prickly dismisses the kid, he commends T.J. on a job well done, but T.J. looks sad. Principal Prickly asks him what's wrong, and T.J. says that the discipline is not strict enough and he requests that his friends be sent up to the office and asks Principal Prickly to leave so he can handle them alone. After he does so, T.J. announces an assembly on the playground one hour before school is let out, which turns out to be a party, sending Finster and Prickly's plan to a crumble, much to their dismay.
- When his friends discover that TJ had been remodeled to resemble Prickly during his stint as principal when addressing the cafeteria, Mikey says "He's more machine than kid now!", referencing a line uttered by Obi-Wan in regards to Darth Vader in Return of the Jedi.