Taichi Yaegashi/Story Plot

Hito Random arc
What would have been an otherwise normal day for Yaegashi Taichi becomes anything but when his fellow Cultural Research Club members, Yui and Aoki, claim to have switched bodies the previous night. Taichi is hesitant to believe their bizarre tale but realizes it to be true when he personally switches bodies with Iori. Escaping from their class representative, Fujishima, Taichi and Iori manage to convince Inaba of their situation before returning to their respective bodies.

The next day, Taichi and the others would learn that the cause of the strange phenomenon is the mysterious supernatural being, Heartseed, who is observing the Cultural Club, hoping to be entertained. Though they resist at first, the club members realize that they stand no chance against Heartseed's powers and resolve to deal with the phenomenon as best as they can, hoping Heartseed will eventually become bored of them.

During one particular switch with Inaba, Taichi's vice president takes the opportunity to antagonize Fujishima by demanding she stay away from Iori, asserting that Iori is Taichi's. Taichi is horrified that Inaba would do such a thing, but Inaba claims to have done him a favor, stating that she knows Taichi is in love with Iori. Understanding how Taichi could never bring himself to hurt others no matter the cost to himself, Inaba dubs him a "Selfless Freak."

After several weeks of body switching with his fellow club members, Taichi would learn that Yui secretly suffers from androphobia, a fear of men. Wanting to help her, Taichi teaches Yui a flawless technique to defeat any man: punting them in the groin. Taichi's lesson restores Yui's confidence and serves as her first step towards overcoming her androphobia.

Later, the stress of the phenomenon gets to Inaba, causing her to faint, and Taichi and Iori escort her home. Afterwards, Iori reveals to Taichi that she suffers from identity loss, admitting that the cheerful Iori he is familiar with is merely a false front she has fabricated. Taichi comforts Iori, declaring that she can rely on him to always know who Iori is at heart and will always be able to recognize her no matter what she becomes.

The next day, Inaba is still in poor condition and Taichi takes it upon himself to look after her. Inaba tries to shoo Taichi away but he refuses to leave her during her time of need. Growing increasingly concerned for Inaba, Taichi demands to know what it bothering her so much that her health is suffering, declaring that Inaba has no right to call him a friend if she insists on hiding her weaknesses from him. Inaba reveals that she cannot trust her friends, terrified of the idea of leaving her body in the hands of someone who could potentially betray her. Taichi suggests Inaba inform the others of her fears, but Inaba refuses, too scared of rejection. Taichi eventually persuades her to do so by revealing a secret of his own to her.

Later, after witnessing Aoki's rejection after confessing to Yui, Taichi encounters Iori who states to be Inaba in Iori's body. "Inaba" questions how Taichi feels about Iori, but before Taichi can properly answer, it is revealed that Iori is merely pretending that Inaba is in control and she leaves in tears. Taichi realizes that he failed to uphold his promise of always being able to identify Iori and gives chase. Aided by Fujishima, Taichi finds Iori on the riverbank bridge and apologizes. He asserts that in the end, Iori will always be Iori no matter what mask she thinks she's wearing and confesses his feelings to her. However, before Iori can respond, she is possessed by Heartseed who states that what he's about to do is Taichi and the others' faults for being so boring and proceeds to jump off the bridge using Iori's body.

Iori is revealed to have survived the fall but is in critical condition at the hospital. As Taichi and the others wait outside the emergency room, they are approached by Heartseed who states that Iori will soon die but they can save her so long as one of them sacrifices themself in her place. Giving the group 30 minutes to willing switch bodies amongst themselves, Heartseed leaves the group. Taichi immediately offers himself up but Inaba berates him for wanting to throw his life away, calling him a "Selfish Freak" for not considering how his sacrifice would make his friends feel. Taichi agrees that he is selfish, admitting that it tears him up to watch others suffer and he would do anything to spare himself the heartache, even if it means sacrificing himself.

Aoki switches bodies with Iori to inform her of her situation, and Iori, refusing to take the lives of her friends, chooses to be the one who dies, but wants to say her individual goodbyes to everyone first. Using Inaba's body, Iori privately speaks to Taichi one last time and asks why he isn't sad like the others. Taichi reveals he is sad, but if he allows himself to cry, Iori won't be able to. Breaking down into tears as Taichi holds her, Iori admits that she loves Taichi but cannot accept his confession because she doesn't have much time left. Instead, she requests a kiss and Taichi complies.

Afterwards, to Taichi's relief, it is revealed that Heartseed was merely bluffing and Iori survives her operation, making a full recovery. With the phenomenon over, Taichi and the others celebrate Iori's eventual return to school and Inaba informs Taichi that she knows he kissed her while Iori was in control, swearing to make him pay.

Kizu Random arc
One month after Iori's return, Taichi has still not settled his feelings with her. One day, while alone in the clubroom with Inaba, the Cultural vice president randomly tries to seduce a startled Taichi. Before the situation can escalate, Aoki and Yui enter the room and a distressed Yui suddenly smashes the club table in half. Taichi can only look on in confusion as Iori comforts a bewildered Yui and Inaba flees the scene.

Back at home, Taichi reflects on the bizarre events of the day when he suddenly gets the uncontrollable impulse to speak with Iori. Sprinting downstairs, a confused Taichi snaps out of his craze before receiving a call from a frantic Iori who claims to have experienced a similar impulse. The two awkwardly take the opportunity to confirm their continued feelings for each other before calling it a night.

Returning to school, Taichi and the others learn from Fujishima that Yui and Aoki were arrested the previous day after Yui assaulted some boys. Becoming suspicious of everyone's strange behavior, the group is visited by Heartseed who reveals that the recent anomalies were his doing. Explaining that his latest phenomenon forces their desires and impulses to go unrestrained, Heartseed bids the group farewell, looking forward to what they will do next. Taichi later recieves a call from Iori who requests they put their relationship on hold until the phenomenon passes and Taichi agrees.

After a few days of dealing with their impulses, the group realizes that Yui has been avoiding school. Taichi and the others visit her at her home where they find Yui hiding away in her room, afraid to leave because she might hurt someone again with her impulses. Unfortunately their attempts to help Yui fail when Inaba loses her patience with Yui and her impulse unleashes, causing her to harshly berate Yui for hiding.

The next day at school, Taichi notices that Inaba is starting to distance herself from the rest of club and is refusing to join them at the clubroom. Inaba insists she will only be detrimental if she remains with the group but Taichi thinks otherwise. When Inaba refuses to rejoin the club, Taichi's impulse unleashes and he accuses Inaba of turning her back on her friends, expressing his disappointment. An ashamed Taichi can only watch as Inaba leaves in tears.

With Yui and Inaba now isolating themselves, Taichi and the others discuss how best to handle the situation. Taichi believes they must keep reaching out to Yui despite the dangers of their impulses, but Aoki criticizes that Taichi's thinking is too reckless. Their argument soon escalates into a full scale confrontation that ends when Iori tries to get between them and Taichi's impulse unleashes, causing him to violently shove her away, injuring her. Taichi is left horrified of his actions and spends the night mulling over how foolish he was to try to be a hero.

The next day, a cautious Taichi remains aloof and distant from Iori and the others and ultimately decides against visiting the clubroom. After school, he is asked to help with an errand by club advisor, Gotou. Along the way, Gotou notices how troubled Taichi looks and advices him to go to his friends for support. Taichi insists that he would only end up hurting his friends if he spoke with them, but Gotou suggests that hurting and relying on each other is what friends are for, which resonates with Taichi.

On their way back to the classroom, Taichi runs into Fujishima, who Gotou asks to counsel Taichi. Taichi asks his class representative what she would do if she needed to speak with her friends, but could potentially hurt them by doing so. Fujishima plainly responds she would speak with them anyways and asks which is more important to Taichi: talking and potentially making things better, or avoiding, but letting things stay the same. Fujishima declares that once Taichi can determine which is more important to him, all his decision will become easy and takes her leave.

The next day, Taichi chooses to meet with Iori at the clubroom, apologizing for his previous actions and the two make up, resolving to put the club back together. Taichi soon after makes amends with Aoki and the two decide to walk home together. Sharing a sunset, the two friends lament how to help Yui when Aoki suddenly gets an idea.

Returning to Yui's home, Taichi watches as Aoki relays his idea to Yui, suggesting that she can control her impulses through sheer force of will. Yui has her doubts, but Taichi adds that now that she understands what it means to truly hurt someone, she won't allow herself to do it again. Yui decides to trust the two boys' theory and agrees to return to school.

The class field trip soon comes around and Taichi and Iori are suprised to find the long absent Inaba ready to go. Teamed up with Iori, Inaba, Fujishima and Watase, Taichi is quickly exhausted by his teammates during their excursion in the mountains. While washing dishes after lunch, Taichi notices that Inaba has a gash on her finger and tries to disinfect it for her, though his attempt only infuriates her. Inaba storms away to get a band-aid and a worried Iori decides to follow. While taking out the trash, Taichi comes across a kitten stuck in a tree and decides to help it get down. Unfortunately, after scaling the tree, he ends up falling and injuring himself, though he manages to save the kitten. His friends quickly clamor around to check on the slightly bruised Taichi and a frantic Inaba soon joins them. Taichi apologizes for making Inaba worry and the vice president suddenly bashes him in the stomach before breaking down into a hysterical sob. A confused Taichi tries to settle her down.

After returning to school, Inaba requests Taichi meet her in private where, to Taichi's surprise, she confesses to have fallen in love with him. Taichi is taken aback, and, while honored, gently turns her down, stating that he is in love with Iori at the moment. To his surprise, Inaba cheerfully states she already knew as much and warns him that she will not give up, hoping to make Taichi fall for her. As a very confused Taichi tries to piece together the situation, Inaba steals a kiss from him, happily stating that she will see him at the clubroom tomorrow. Taichi, dumbfounded, looks on.

Asu Random I arc
Upon realizing that his memories of the Cultural Club and phenomenons are gradually being erased, Taichi slowly descends into panic. He begins obsessively writing, with shaking hands, the names of his fellow club members in a notebook and reviews past photos to keep his memory fresh. His habit becomes so serious that Rina becomes worried that something is wrong with him. Taichi's mother initially believes his behavior is simply due to puberty and other typical teenager issues but eventually becomes suspicious as well.

After most of the student body are trapped in the Isolation Dimension by No.3, Taichi considers abandoning them, afraid to take the risk that his memories of the StuCS could be lost trying to save his classmates. At this point, Taichi is frequently being called by a worried Rina, though he refuses to answer his phone due to the pressing matters at hand.