By the Time We Realized It, It Had Already Begun (気づいた時には始まっていたという話 Kizuita Toki ni wa Hajimatteita toiu Hanashi) is the first episode of the anime series.
Narrating how at Yamaboshi High, all students are required to join a club, Taichi describes the many coincidences that eventually led to the five, very different students, establishing the Student Cultural Society club.
With classes finished, Taichi arrives at the StuCS where he encounters its vice president, Inaba, diligently typing on her laptop. Inaba asks Taichi if he has a topic that they can write their club article about and Taichi enthusiastically proposes they report on the history of pro-wrestling techniques. Before he can elaborate, Inaba cuts him off, not having the patience to listen to Taichi's spiel. At that moment, club president Iori flamboyantly enters the room. She lounges on the room's sofa, exposing her shorts under her skirt and jokingly offers to let Taichi peek for 120 yen. Though embarrassed, Taichi mentions it to be a good deal and Inaba notes how inappropriate the whole situation is.
Getting back on topic, Taichi asks Iori what she would like to write the club article about and she suggests spicing up their news with sex and violence. Inaba states no one reads their articles for thrills but Iori insists that they just need Inaba to model for sexy photos. Unwilling, Inaba points out Iori would be better suited for the role but the club president suggests that she only provides innocent fanservice while Inaba is perfect for more sensual functions. Deciding to put their debate to the test, the girls ask Taichi which one of them he, as a high school male, would rather see naked. After some careful consideration, Taichi responds "both" and Inaba immediately starts documenting his answer, Iori planning on adding his supposed desire to have them strip to their article. At that moment, Aoki and Yui enter the room.
Clearly worried about something, Aoki and Yui try to find the right words but Inaba impatiently urges them to spit it out. Building his courage, Aoki reveals that the previous night, he and Yui switched bodies. Aoki is quickly met with a strike from Inaba, who demands he stop joking around but the blond StuCS member insists he's telling the truth. Iori and Inaba suggests Aoki merely dreamt of switching bodies with Yui, considering his history of asking Yui out to no avail. Aoki elaborates that he woke up the previous night in Yui's room and when he checked a mirror he only saw Yui's face. Though sharing a similar experience, Yui begins having her doubts and accuses Aoki of influencing her with his perverted fantasies. Yui concludes that everything they experienced was indeed a dream but can't figure why she and Aoki would have the same dream at the same time. Aoki decides to take it as a sign that they're fated to be together, much to Yui's annoyance.Suddenly, Iori remembers she left her notebook in her classroom and leaves to retrieve it. Commenting how spontaneous Iori can be, Taichi offers to prepare some tea when suddenly... he finds himself in a totally different room. Confused, Taichi realizes he is somehow in his homeroom and, upon further inspection, finds he has suddenly developed very feminine physical traits. Exploring the breasts that he suddenly possesses, he is discovered by class representative Fujishima who addresses him as Iori. Trying to put two and two together, Fujishima suddenly closes in on Taichi (in Iori's body) and offers to help him fondle himself, much to Taichi's horror. Insisting that she's skilled with her hands, before Fujishima can do anything, Iori (in Taichi's body) explodes onto the scene, frantically demanding Taichi come with her. However, Fujishima refuses to let this opportunity pass her by and the two wrestle over Taichi (in Iori's body). Fed up, Iori (in Taichi's body) resorts to tickling Fujishima and she and Taichi flee the scene, leaving their confused class representative behind. Having managed to escape, Taichi and Iori conclude that they have indeed switched bodies with each other and realize Aoki and Yui were telling the truth.
Returning to the clubroom, Taichi and Iori explain to their friends that they have switched bodies. Yui and Aoki are immediately convinced as Iori (in Taichi's body) is way too cheerful, which depresses Taichi. A frustrated Inaba, unable to comprehend the bizarre situation, punches the table and Taichi points out she must have hurt herself. Enraged, Inaba lunges at Taichi (in Iori's body) but stops herself upon realizing she'd be hurting Iori. Aoki summarizes that by stopping herself, Inaba has proven that she is beginning to believe their story, but the vice president adamantly believes it to be some sort of elaborate prank. Iori suggests that Inaba would be more open to believing if she herself experienced the strange phenomenon.
Unconvinced, Inaba decides to interrogate Taichi (in Iori's body) on topics only the real Taichi would know the answers to. Taichi agrees and Inaba questions what was the title of the most recent adult video Aoki shared with him. Taichi almost immediately starts listing the title, but stops himself upon realizing everyone can hear him, only blurting out "Big Boob High-". Getting sickening looks from Yui and Iori, an embarrassed Taichi asks if he can merely whisper the answer to Aoki and Inaba allows him. After whispering, Aoki confirms it to be the correct answer, in addition to being excited that he heard Iori's body say something dirty. After establishing that (to Taichi and Aoki's apprehension) both male members like big breasts, Inaba deviously turns her attention to Iori (in Taichi's body), which frightens everyone. Inaba chooses to whisper something unheard into Iori's ear, which causes her to freak out, lamenting how they are indeed grown-ups. Having the evidence she needed, Inaba admits to believing the body-switching phenomenon, though she wonders how they should go about handling it. Aoki states that he and Yui only switched bodies for about a half hour and at that moment... Taichi and Iori suddenly realize they've returned to their respective bodies, much to Inaba's added frustration.
Walking home, the StuCS wonder if the mysterious phenomenon is over and Iori suggests they keep it between themselves. After a long day of strangeness, everyone returns home to their families and normal lives.
Differences Between Novel and Anime
- When Iori charges Taichi to have a peek, Inaba did not mention that it was borderline illegal to Taichi in the anime.
- Taichi mentions a wrestling move known as the Brainbuster, which is a move where a wrestler puts the opponent in a front face lock and then lifts the opponent up and drops the opponent on his/her head.
- According to exchange rates as of January, 2010, ¥120 was equivalent to about $1.30 in the U.S.
- The ice cream place where Taichi and Rina went to is a Baskin-Robbins.