K.O. and T.K.O decide to swap places for the day.
K.O. arrives home from school and follows his after-school rules, which includes doing his homework, putting his stuff away, and washes up so he can be ready for his favorite after - school snack, one chocolate chip cookie with a glass of milk.
Carol notices K.O. follows his after-school rules without a hitch and trusts him to stay home alone while she runs some errands. Carol reminds K.O. to follow the rules and stay out of the construction zone and then leaves. K.O. is tempted to snatch a second cookie but resists.
K.O. decides to "keep his mind busy" by paying T.K.O. a visit in his brain, now that they are close. When K.O. arrives, T.K.O. is playing video games and complains about their mom's rules. K.O. counters, stating that he enjoys going to school and working at the plaza while saying he's lucky to get one cookie per day. T.K.O. hastily explains that they're "not just some little kid" anymore, and that they're Level 4 now, and that they should have to freedom to do whatever they'd like. K.O. trusts T.K.O. to swap places while Carol is gone, and T.K.O. hastily accepts. T.K.O. then begins to break his mom's rules, including eating multiple cookies and making a mess without cleaning it up.
Meanwhile, K.O. is enjoying his video game when the system asks to update the game, which K.O. accepts. Back in the real world, T.K.O. finds a list of Carol's rules to break, and proceeds to do so.
Back in the brain, K.O.'s update completes but then takes more time to install it, much to K.O.'s dismay. K.O. becomes impatient, and decides to clean up T.K.O.'s house while he's waiting, doing it as a favor for T.K.O., since he's been so nice to him.
T.K.O. continues breaking his mom's rules, and trashes his house, before letting a bunch of baby dinosaurs inside. K.O. continues cleaning up while T.K.O. wrecks havoc some more. T.K.O eventually spreads his wrath to the construction zone. K.O. is almost finished with T.K.O.'s house when he pulls a blanket off the K.O.-Vision and discovers what his alter-ego has been up too in the real world.
Angered, K.O. sends T.K.O. back to his brain. T.K.O. attacks K.O., causing the latter to stub his foot, but K.O. eventually defeats him. K.O. scolds him, disappointed that T.K.O. broke his trust, damaged his house, and broke their mom's rules.
T.K.O. tries to justify his actions, but K.O. explains that the rules are in place for a reason, even if they feel unfair. K.O. leaves T.K.O.'s house to take responsibility for the mess he made. T.K.O. enragingly states that the only rules he cares about are his own. When Carol arrives at the house, K.O. is cleaning up his alter-ego's mess but takes responsibility for T.K.O. eating all the cookies. Carol thanks K.O. for being honest with her and gives him another cookie.
Later, K.O. reluctantly decides to punish T.K.O. for his actions. K.O. asks T.K.O. to enter an elevator and tells him that he's given up on him and that he has broken his trust. K.O., out of character, pushes T.K.O. down to his subconscious, throws him his cookie, and welcomes him "home".
T.K.O breaks down in tears after K.O. leaves, ending the episode.
- This is the last episode Geneva Hodgson storyboarded as she moved up to supervising director but later returned to board a short scene in "Thank You for Watching the Show".
- T.K.O. references the episode's title when he yells at K.O. by saying: "The only rules I follow are T.K.O. Rules!"
- Throughout the episode, four drawings flash across the screen in different scenes.
- The book where T.K.O. and K.O. read was all about Carl Jung's Shadow theory, was related to K.O.'s dark alter-ego.
- During the middle of the episode, T.K.O.'s drawings flashed every second was probably related to how he will deal with his mental issues.
- Near the end of the episode where before K.O. shove T.K.O. back to his Subconscious, the elevator scene was referenced to Japanese animated series Neon Genesis Evangelion.
View the episode's transcript here.