"Emotion Sickness" is the fifty-third episode of Kim Possible and the second episode of the third season.
While preparing for the Middleton Days event that will be happening on the coming weekend, Ron - dressed up as pickle mascot 'Kosher Dilli', is conversing with Kim. While they're talking he sees Kim's crush, Josh Mankey walking arm-in-arm with Tara. Ron tries to distract Kim from the couple, believing that she still has a crush on Mankey. It seemed to work, until Bonnie comes over and taunts Kim about the fact that Mankey's new girlfriend is not Kim. But, to her and Ron's surprise, Kim dismisses Mankey's relationship with no emotion, saying she and Mankey grew apart. Once Bonnie departs, Kim remarks that she's surprised Ron isn't the downcast one. Confused, Ron soon discovers that Tara had a widely known long-term crush on him which he was completely oblivious to. Ron is frustrated that no one bothered to mention this to him. Then Wade calls in, asking whether Ron is okay with the relationship - verifying how widely known Tara's feelings were. After that he proceeds to inform Kim and Ron that Drakken is on the move. Ron tries to tug off his pickle outfit, but Kim drags him away in a hurry before he can take it off.
Dr. Cyrus Bortel is currently testing his newest invention: Moodulators, small devices that stick to a person and can be used to control their emotional state via a Moodulator controller. Dr. Bortel test the device on himself and goes through a series of emotional states before removing the Moodulator. He comments excitedly on his successful invention and his expectations for which government might be the highest bidder to acquire the new technology before he departs from his lab to watch a Fearless Ferret marathon. As soon as he is gone, Shego and Drakken break in with the intention of stealing an Electron Magneto Accelerator (EMA). Shego remarks on Drakken's tendency to steal other people's inventions instead of making his own, despite being a 'genius'.
Kim and Shego are fighting, when they hit the bookshelf, the experimental, A Moodulator gets attached to Kim's neck and a few seconds later, another attaches to Shego as well. Shortly after the fight Drakken and Shego escape with the EMA, so Kim and Ron also leave the lab although with a somewhat stunted pride. When Dr. Cyrus Bortel eventually enters his lab again, he is shocked about what has happened, and then finds the Moodulator controller missing, this was when Ron picked up the wrong controller, by picking up the Moodulator controller. Chaos later approaches, when Kim and Ron gets to Kim's home, because Kim has now discovered that Ron actually picked up the Moodulator controller and not the Kimmunicator. Kim informs Ron about his mistake then throws the moodulator to him. Ron thinking that the Moodulator control is a video game, immediately starts playing with it. This activates the Moodulator chip on Kim's neck and turns her utterly sad and devastated because they have lost the Kimmunicator, Ron on the other hand becomes very confused because of Kim's sudden mood swing.
At the same time in Drakken's lair Shego is seen crying because of a broken nail, but Drakken can't wrap his head around why Shego would cry for something as petty as a broken nail, especially since they managed to escape with the EMA. Back at Kim's house Ron and Rufus tries to cheer her up, but to no avail, Ron then suggests that Kim play a game on the Moodulator to feel better, but he manages to press a button on the Moodulator control and change it's setting to anger. This prompts Kim to immediately turn very angry and proceed to drag Ron by the shirt to school, in order to inform Wade via the computer in her locker that Ron has lost the Kimmunicator.
At Drakken’s lair Shego experiences the same mood change as Kim and thus instantly turns unreasonably angry at Drakken and grabs him by the collar of his shirt and pins him against a supporting beam in the lair. When Drakken then mentions that Shego overreacted she becomes even more furious and throws Drakken across the lair and attacks him with her energy blasts. The Moodulator, left behind by Kim and Ron as she dragged Ron to school, is now found by Jim and Tim. Upon finding the device they start to ponder on what type of device they might have found. They don’t make any conclusions but instead start to fight for the device and in the turmoil presses it’s buttons many times causing the mood symbol on the device to cycle through many of the different emotions.
In the meantime Drakken tries to hide from Shego in his lair to escape her wrath, but is quickly found. However when Drakken is found by Shego, due to the actions of Jim and Tim, she suddenly starts to change emotions rapidly, this confuses and scares Drakken even more and as he lays down in a fetal position he asks Shego if she behaves strangely because Drakken has forgotten her birthday.
As Ron and Kim arrive at Middleton, Kim also starts to cycle through different emotions, which Ron thinks is very random, but as he sees Josh Mankey and Tara walk by he concludes that Kim’s random behavior must be due to her trying to cope with the fact that Josh is dating Tara now. Although while Ron tries to explain to Kim that he understands her behavior, he clumsily says the it was Kim who lost the Kimmunicator and this happens just as Kim turns Angry again. Kim therefore proceeds to drag a protesting Ron by the collar to her locker. There she urges Ron to tell Wade how he lost the Kimmunicator, but as Ron explains this to Wade Kim’s mother breaks up Jim and Tim’s fighting back at the Possible’s house and takes the moodulator from them and at the same time accidentally sets it to love mode. This causes Kim to fall madly in love with Ron and thus she interrupts Ron’s confession to Wade and says that the loss of the Kimmunicator was merely an accident. Wade agrees with Kim and start working on finding the Kimmunicator, while Kim moves very close to Ron and plays with his shirt, to Ron’s annoyance. Shortly afterwards Kim closes the door to her locker and tell Ron that they need to be going and gently pulls him in the arm to make him come with her to their next class. Before taking her seat however, Kim gives Ron an air kiss and tells him that they will see each other after class, but Ron just stands there looking scared and confused because of Kim’s strange behavior. Bonnie sits in the back of the class and sees the unordinary interaction between Ron and Kim and simply proclaims that some things are just too weird to think about.
Back at Drakken’s lab he is busy working on the EMA, when he suddenly notices a smiling Shego laying on his work table on her stomach. Even though she is smiling at him, Drakken still asks her if she is mad at him, to which Shego answers no and tells him that she is merely admiring his EMA while gently poking at Drakken’s nose. Suddenly Drakken notices that Shego looks at him very lovingly and asks why she is looking at him like that, Shego responds by saying that she never before has noticed how blue and deliciously evil Drakken is. Drakken who is somewhat flattered and unsure how to deal with Shego’s current emotions asks her if she doesn’t have anything better to do. Shego agrees and then proceeds to use her energy blasts to carve a heart in the wall with her and Drakken’s initials. She then starts acting like a cat and claws with her fingers in the air toward Drakken, but he won’t play along and instead moves away to try his EMA on the thermostat. With the air conditioner supercharged by the EMA Drakken manages to fill the entire room with snow and freeze himself for a couple of seconds. This result makes Drakken very pleased and he exclaims that it worked better than he imagined. Shego then suddenly appears having grabbed a winter jacket and a couple of mugs with latte and offers Drakken some cuddling and latte. Drakken would like the latte, but is not interested in cuddling, when Shego asks why, Drakken says that she freaks him out, but Shego then quickly changes Drakken’s mind by massaging him before dragging him away to have some “breakey poo”.
Back at Middleton high Ron’s confusion and astonishment continues as Kim further displays her affection for him by sending him a heart filled note with his name on during class. Meanwhile Drakken and Shego visits a park where Shego steals some candy for him and later they take some photos in a photo booth. Then, after class a terrified Ron is chased around the School by Kim who tries to flirt with him and kiss him but without success. Later while Monique is cleaning one of the floats at the school gym she is approached by a sneaky Ron in his Kosher Dilly suit and tells her about Kim and that she is crushing on him which is freaking him out. Monique only finds Ron’s situation humorous and before long Kim has found Ron again and tries to ask him about a favour, but Ron quickly escapes. Kim quickly resumes her chase this time taking it one step further by using her grappling gun and hiding inside the ceiling and finally manages to catch Ron next to her locker. Here Kim asks Ron the favour, which is that she wants him to be her date for the Middleton days festival, Ron doesn’t give a straight answer but Kim interprets this as a yes and kisses Ron just as Wade appears on the computer screen in Kim’s locker. Wade is majorly shocked and confused, but gets no answer from the lovestruck teens before they close the locker door and head home to prepare for the festival. Later Ron is now in a living room and contemplates what to do, because even though he enjoyed the kiss and thinks it could be exciting to date Kim, he is afraid that their friendship could be ruined if the dating doesn’t work out. Therefore he decides that he is going break up with Kim to save their friendship and thanks Mr. Barkin who is sitting on the other side of the room for the advice, but Barkin is only annoyed by the fact that Ron has entered his living room and house uninvited.
Meanwhile Dr. Bortel is worried about his auction that is soon about to end, because he doesn’t have his Moodulators that he was going to sell, but then notices the Kimmunicator that starts to fly away from his lab. Nonetheless, Dr. Bortel quickly starts to pursue the Kimmunicator hoping to find his Moodulators. Back at Drakken’s hideout, he and Shego is enjoying a milkshake together, when Shego suggests that they should do something evil. Drakken happily agrees and says that they should go to the Middleton days festival and use the EMA to supercharge the laser on the spaccenter’s float to use it as a doomsday ray. Shego however is more thrilled to go to the festival as Drakken’s date and gets her will through by threatening him.
Not much later Ron is standing outside Kim’s house trying to figure out how he is going to break up with her. However, as he knocks on the door he is quickly greeted by Kim’s parents who are thrilled that Ron and Kim is going on a date. Though, they still start to have a serious talk with Ron about Kim and him as a couple which ends with Kim’s dad threatening to send Ron to a black hole if he hurts Kim’s feelings. Ron then grabs the Moodulator control, which he still thinks is a game, to entertain himself while waiting for Kim, but suddenly Kim greets Ron from the dorway across the room in a stunning black dress, which makes Ron’s jaw drop. In no time Kim has grabbed Ron and they are of to the festival, but not before Kim’s dad manages to tell Ron that Kim is to be home no later than ten.
At a fair on the festival Kim and Ron plays a game at one of the stands, before Ron tells Kim that they need to talk. Ron tries to reason with Kim why they should break up, but the Moodulator control is in his back pocket and as he sits down Kim’s feelings rapidly changes before ending at sadness right as Ron tells her that they should break up, therefore she proceeds to run away crying much to Ron’s despair. However, before Ron can put anymore thought to his break up problem the Kimmunicator flies into his head followed shortly by a an angry Dr. Bortel, who thinks Ron is a spy. Nevertheless, a short conversation between Ron and Dr. Bortel clears the misunderstanding and also begins to inform Ron about the Moodulators.
In another part of the festival Drakken struggles with a crying Shego whose mood was also changed when Ron sat on the moodulator control. Although Shego feels betrayed by it, Drakken still decides to leave her as she cries to go and supercharge the laser on the spaccenter float. On his way to the float he notices a crying Kim Possible running towards him, he therefore proceeds to quickly hide in a bush to avoid her. Her unusual crying does nonetheless puzzle Drakken, but the answer arrives as fast as the question, when Dr. Bortel and Ron walk past his hiding spot talking about how the Moodulators work. In no time Drakken exits the bush and overpower Ron and Dr. Bortel to take the Moodulator control and supercharge it, so that he can control Kim Possible. Instead his plan backfires frying the Moodulator control and sending Kim and Shego into an irreversible frenzy of rage. Then in no time Kim finds Ron and starts chasing him furiously, this makes Drakken burst into laughter, but he is interrupted almost immediately when Shego finds him and begins to chase him with a fury equaling that of Kim. Ron tries to calm Kim down while she is chasing him, but to no avail. So shortly after running past Drakken and Shego Ron decides to hide in the pickle float and inside he finds out that Drakken has had the same idea. Nonetheless none of them manages to hide for long before Kim finds them.
Ron runs away again but this time Kim catches up to him and begins to throw him around in anger, and he is eventually thrown into Shego. This causes Shego to direct her anger at Ron for the moment. Ron fearing Shego’s wrath calls out to Kim for help just before dropping his pants while dodging one of Shego’s plasma infused strikes. Kim seeing that her best friend is in danger manages to overload the moodulator frying it and thus freeing her from its control. Ron feeling embarrassed without his pants runs up to a nearby Mr. Barkin and takes the pickle suit he is wearing to cover himself up. Shego is however hot on Ron’s trail, but before she reaches him she is tackled away by Kim. Kim now approaches Ron and let’s him know that she is no longer angry and free from the moodulator. Drakken now approaches Kim and Ron, expressing bitterness that Kim is back to normal, but his bitterness quickly changes to fear when Shego finds him again, still affected by the moodulator. While Drakken runs away chased by Shego Ron nervously asks Kim if her crush on him was only caused by the moodulator, with a smile on her face Kim ambiguously answers that there is still fireworks before she points up at the sky where fireworks can be seen.
- This is the first time Kim and Ron have actually kissed, unless one counts Kim kissing Ron on the cheek under the makeshift mistletoe in "A Very Possible Christmas".
- According to Steve Loter, the producer of the series, the episode was a test to see how the fans would react to the possibility of Kim and Ron having a boyfriend/girlfriend relationship.
- The episode was voted #1 in the Disney Channel's "Kim Possible Click it to Pick It: So the Countdown".
- In the previous episode, "Steal Wheels", after Drakken and Motor Ed stole Felix Renton's wheelchair, Shego asked, "What's next, candy from a baby?" In this episode, she did just that.
- When Ron is talking to Kim at the Middleton Days Festival and accidentally presses a button on the moodulator, the device is in his left pocket, however when he takes it out to show Cyrus Bortel he takes it from his right pocket.
- Twice, the moodulator control shows a purple gloomy face instead of the blue crying face: When Dr. Bortel is testing the moodulators at the beginning, and when Jim and Tim are fighting.
- When Dr. Possible takes the Moodulator control from the twins and sets it on the table (inadvertently turning it to "Romantic"), the face on the screen is the purple "Romantic" face before the button sound effect.
- During the musical interlude when Ron is fleeing Kim and Shego and Drakken are in the park, Ron crouches at a corner with lockers on either side of the wall. When Kim surprises him from behind and the view switches, the left wall is still lockers, but the lockers around the corner have vanished and been replaced by a door.
- Though this was the second time that Dr. Cyrus Bortel had met Kim and Ron, he did not seem to recognize either one in this episode. His mistaking Ron for a spy was understandable as people commonly forgot Ron. But Bortel knew Kim on sight when they first met, yet he never referred to her by name in this episode. Although oddly enough, Ron did not seem to remember Bortel, either.
- One of the floats at the beginning of the episode features Ron's supposed ancestor from "Rewriting History".
- When Kim wins the pickle doll for Ron at the fair, the other competitors are wearing Rocket Booster sweatshirts from "Monkey Ninjas in Space".
- Another boy skating in the park during Drakken and Shego's outing also was wearing one.
- This is Dr. Cyrus Bortel's second appearance, having first appeared in "The Twin Factor". It is also the second time Team Possible had to deal with his mind-altering technology in Drakken's hands.
- Shego says "You talkin' to Me?" - one of the most famous Robert De Niro lines from Martin Scosese's, Taxi Driver.
- Kim says "You got some 'splaining t'do!" - a catchphrase from I Love Lucy.
- The mood swings of Kim and Shego are similar to the Emoticlones of Raven in Teen Titans.
- When Kim and Shego get angry and halves of their faces appear on a splitscreen, it is similar to how Bruce Banner turns into the Hulk.