In 1995, Mimi lived in Highton View Terrace with her parents, Kēsuke and Satoe Tachikawa. One night, she witnessed the battle between Greymon and Parrotmon. This event led her to be chosen to become a new DigiDestined. The destruction created by the battle caused it to be labeled a terrorist attack, and the Tachikawa family moved away from the area.
When she is transported from summer camp into the Digital World, Mimi's pampered background and inexperience lead her to grow tired easily and complain. However, she does the best she can to keep up with the others. To her chagrin, she finds out she is very popular with gross Digimon like Numemon. When Devimon separates the DigiDestined, Mimi and Palmon end up in the Ancient Dino Region. When they encounter Sukamon and Chuumon, Mimi's Digivice purifies the naturally nasty Digimon, and they tell Mimi and Palmon they saw another human on the other side of the region. When they find Izzy Izumi and Tentomon at a temple, Izzy is too preoccupied to recognize Mimi's presence, and she is insulted and runs away crying, with Tentomon in hot pursuit. When they both run into a maze, Izzy pulls out the map and locates Mimi’s, directing them out of the maze. After Tai and MetalGreymon disappear following the battle against Etemon, Mimi and Palmon break from the other DigiDestined. Mimi is sought out by Gekomon and Otamamon from ShogunGekomon's castle, who were told by DemiDevimon about her singing skills. They bring her to the castle, hoping her singing will awaken ShogunGekomon, but Mimi takes advantage of their hospitality and asks for more and more luxuries. When Tai and Joe arrive and try to take her with them, Mimi refuses, even throwing them and Palmon to the dungeon. However, she feels terrible for betraying her friends, and when Sora Takenouchi visits Mimi in her bedroom that night, she admits she had been wrong. She apologizes to her friends and the Gekomon and Otamamon and sings to ShogunGekomon, waking him up. After ShogunGekomon attacks them and the DigiDestined defeat him to save the Gekomon and Otamamon, Mimi rejoins the DigiDestined. Soon, the DigiDestined reunite and return to the Real World with their Digimon, hoping to find the eighth DigiDestined before Myotismon and his army get to them. However, on August 3, Myotismon sends his Bakemon to capture everyone in Odaiba, Mimi and her parents among them. While they are help at the Tokyo Big Site convention center, Mimi and Sora reunite, and with the help of Tai and Mimi's parents, they manage to escape momentarily. When DarkTyrannomon appears and holds them back, Mimi's Crest of Sincerity activates, and Togemon Digivolves into Lillymon to neutralize him. However, Myotismon decides to take on Lilymon himself, freezing her. Though Sora manages to escape, everyone else is taken back to the convention center. However, when Myotismon puts everyone in the convention center under a sleep spell, Mimi's Crest awakens her immediately, and she joins the other DigiDestined and the revitalized Lillymon to fight Myotismon. Once they return to the Digital World, many of the DigiDestined's friends sacrifice themselves to save them from the Dark Masters. Mimi is deeply saddened by these deaths, to the point where she feels she can no longer fight. Joe decides to be the one to stay with her so she wouldn’t be alone. Once they are alone, they encounter the wounded Ogremon, and Mimi asks Joe to give him medical aid. When the newly evolved MetalEtemon attacks them, their old friend Leomon comes to their aid as SaberLeomon. However, in a later battle against MetalEtemon, SaberLeomon is gravely injured, though he helps Zudomon defeat MetalEtemon before he perishes. Now realizing that she has to fight to prevent more friends from dying, Mimi decides gather all their Digimon friends to help them in the final battle again Piedmon. After spending some time gathering reinforcements, Joe leaves Mimi with them to find Matt. When the DigiDestined gather to battle Piedmon and MagnaAngemon ruins his plan to turn the children into keychains, Mimi arrives at the battlefield, having gathered more friends to fight since Joe's departure. With their help, the DigiDestined easily overpower Piedmon and his army of Vilemon. After defeating Apocalymon, when it's time for the DigiDestined to go back to the Real World, Palmon suddenly disappears. Mimi boards the tram back to the Real World thinking that she missed her chance to say one last goodbye to her partner. Once the tram starts moving, however, Palmon appears, having been too upset to say goodbye. Mimi's hat flies off in the wind as the DigiDestined and the Digimon wave goodbye to each other.
Digimon: The Movie
On March 4, 2000, Mimi is taking a vacation in Hawaii. When Tai tries to call her in a panic, he can't reach her, only to later receive a postcard from her.
T.K. and Kari visit Mimi in New York on summer of 2002. After she takes their picture, she goes to a telephone booth to connect her laptop to test the connection, but disappears into thin air few moments later, leaving T.K. Takaishi and Kari Kamiya confused. She is kidnapped into another dimension and regresses in age thanks to Wendigomon, but the new DigiDestined reverse this.
Digimon Adventure 02
On May 2000, Mimi arrives in the Digital World and gives up her Crest power to free the Digimon Sovereigns. As a result, Palmon loses the power to become Lillymon.
y 2002, Mimi has been fully acclimated in America, though she also misses Japan, especially her friends and Japanese food. During Golden Week, Mimi comes back to Tokyo for a visit (in the Japanese version, it is stated that Mimi returns to Japan to attend her cousin's wedding) and meets the new DigiDestined, joining them on a picnic. Later, a portal to the Digital World opens in the United States, allowing Mimi to access the Digital World. She uses this opportunity to introduce the new DigiDestined to her friend Michael, who is one of the American DigiDestined. During the summer, she visits Tokyo again to celebrate the anniversary of her Digital World adventures with the other DigDestined. In autumn, while Mimi is feeding a bunch of YukimiBotamon/SnowBotamon, Palm=on sees Arukenimon converting a Control Spire into Golemon and ordering it to destroy a nearby dam. Mimi messages the new DigiDestined to come help, and after all five of the DigiDestined's Digimon are exhausted and defeated, Mimi messages Ken to come help. This proves to be a turning point for the DigiDestined's relationship with Ken. On Christmas Day, Mimi receives a special present from the younger DigiDestined: they bring Palmon to the Real World, and she hides in a sack under the Christmas tree. That night, when Digimon are set loose worldwide, Mimi's frightened parents try to take her and Palmon and leave the city. However, the two escape from the car, and join Davis and Michael to help them gather all the loose Digimon and send them to the Digital World. When the world is engulfed by MaloMyotismon's darkness, Mimi is with the American DigiDestined in New York, holding her Digivice to the sky with the others. They manage to reach the Digital World from there, and help defeat MaloMyotismon once and for all with the light of their Digivices.
Digimon Adventure 02: The Movie
On March 2003, she was traveling to Japan by plane and later showed up at the school computer lab where Izzy, T.K. and Kari were.
Digimon Adventure tri.
Izzy decides to text Mimi, who accepts but asks them to cover her airfare from New York; the prices make Tai balk.
DigiDestined appear, all with their partners—save for Mimi, who just landed in Narita Airport. Himekawa picks up Mimi. They are then escorted home without answers, though Mimi reveals that she's returning to Japan for a while. DigiDestined hear about the injuries caused by the battle, including those who wish that all of the monsters would disappear. At the same time, Mimi and Meiko officially transfer to the school, with Mimi ending up in Izzy's class and Meiko in Tai and Sora's class. After school, the DigiDestined meet underneath a bridge to discuss the situation. Izzy begins an update on the situation, including the fact that the gate to the Digital World has been closed for over a year. The DigiDestined, save for Matt and Joe, meet the next day at Izzy's office, where he helps out his American friend's firm. Izzy then displays his new development: a virtual cyberspace that allows the Digimon to evacuate in a hurry through monitors connected to the internet and also allows them to communicate via text. They decide to meet again on Saturday. The DigiDestined spend the day searching and then meet Meiko, who is looking for her cat. They help out, and though they fail, they have fun together. Mimi suggests going somewhere high. They single out Odaiba's ferris wheel when Matt joins them, and the others force the two into a single car to sort out their differences. They do not get very far into their conversation when Tai then puts on the goggles and sees a massive distortion in the sky. DigiDestined attack to protect them. Meiko introduces Meicoomon as her partner, revealing her status as a DigiDestined, and is immediately welcomed into the fold.
Mimi organizes a large trip to Ooedo-Onsen Monogatari to welcome Meiko to the team as well as try to help Tai and Matt patch things up. Meiko almost arrives late due to her indecision in what to wear to make a good impression, gaining no help from Meicoomon, while Mimi has to retrieve Tai and Kari herself. They bring their Digimon partners and, despite being told to lay low, get into their usual hijinks while under the supervision of Himekawa, Nishijima, and their organization. Mimi distracts the men in the dressing room, Sora, Meiko, and Kari rush in to rescue the two. With their trip a success in that Meiko is welcomed into the group, though Tai and Matt remain at odds, they return to their homes. At school, Meiko joins the school festival committee alongside Mimi. When asked for suggestions, Mimi immediately volunteers to lead the committee to using a café idea with a Daters theme where all the girls wear revealing cheerleader outfits. Despite her enthusiasm, she fails to the lukewarm response from the rest of the committee, though her suggested is carried due to a lack of outspoken opposition. Mimi takes Meiko to gather ideas, and Meiko manages to come up with a design while they are joined by their Digimon partners. Mimi decides to use the cameras to boost the Digimon's favor in the public eye and has Togemon attack Ogremon. After the others sans Joe arrive, Izzy grills Mimi for her selfish and egocentric behavior causing more harm than good. Mimi returns home in a funk. The next day at school, Mimi is dealt further blows when the rest of the girls at the committee finally announce their dislike of the cheerleader outfits and reject her proposal, calling her egocentric as well. Mimi snaps at Sora and Meiko when they reveal the outfits they made, which makes her run off in shame. Mimi runs home in the rain, saddened by the events of the day, she spies Joe who is lamenting about his position in life. She asks him if she is egocentric. Joe does not deny it, but he also tells her that at least her selfishness lets her act, in contrast to how Joe's fear and stress paralyze him. Tai then arrives with Leomon, who informs them of the terror the infection has unleashed on the Digital World. He decides to aid them as best he can between the worlds. Mimi arrives at the school to find that Meiko has decided to wear the outfit anyway, finding it would bolster her. Mimi is heartened by this act and decides to wear the outfit as well; though the rest of the class only wears normal outfits, it is enough for Mimi that everyone is comfortable.
Mimi regains faith in herself as well and helps Togemon her own Mega level in Rosemon. Reunited, everyone wonders what has happened to Ken to make him take the persona of the Digimon Emperor again. As the fully reunited DigiDestined discuss their next plan. Meicoomon tears Leomon apart to the DigiDestined's horror, though Himekawa has a smirk unseen by the others. The DigiDestined try to deal with what they just witnessed.
Mimi enjoys how everyone liked the festival and how the other girls will reconsider her "Cosplay Cafe" idea next year, however, the mood shifts when the girls bring up Meiko Mochizuki's disappearance. Remembering Meicoomon going berserk, Mimi looks for Meiko Mochizuki to console her, but Meiko flees and breaks down into tears. Izzy quarantines the Digimon partners in a special space to keep them safe while desperately trying to come up with answers. Because all his tests fail, he begins to pressure Meiko for information on Meicoomon's infection, causing her to break down and Mimi to berate Izzy for his insensitivity to her plight. Izzy however reminds her of the potential spread of the infection takes more of a priority. Mimi and Izzy argue until Sora Takenouchi intervenes and Meiko pleads forgiveness. Meiko returns to school and is reunited with the others who have called an emergency meeting. Mimi tell her story to Palmon, she ask Palmon about her story is not funny, Palmon say her story is fun and ask Mimi what is story about and Mimi say Palmon is funny. The others fight off the infection just long enough to force them all back into the distortion as the reboot occurs. All of the DigiDestined break down into tears at the loss. DigiDestined cannot help but remember their partners even as they return to their daily lives. Everyone decides that they're sick of waiting. With the resolve to move forward, they resolve to make their way into the Digital World. As the others tell Nishijima and Himekawa their plan. T.K. tells them where they're meet and meets up with the others. Using the power of their Crests as well as Ken's D-3 and D-Terminal, they are able to force a portal to the Digital World, through which they enter. In the Digital World, the DigiDestined admit something feels off. They're interrupted by Alphamon and Hackmon, clearing Mega-level Digimon, fighting. They escape and then hear a familiar whistle. They follow the sound to see their partners playing around in their In-Training forms. Tanemon and other Digimon do not remember them, but the DigiDestined decide to befriend them from scratch.
As the DigiDestined try to rekindle their friendship with their partner Digimon. While the others get along well with their partners. They briefly come across Meicoomon, who has retained her memories despite the reboot.
Later that night, Mimi and DigiDestinds are suddenly attacked by Machinedramon, whose attack disperses the DigiDestined and Digimon across the Digital World.
Mimi & Tentomon
Dark Gennai is thwarted by Mimi and other DigiDestineds, who come to their aid. Dark Gennai reveals that the reboot was all part of King Drasil's plan to create a new world order where humans and Digimon no longer interact with each other.
Mimi and DigiDestineds try to survive the Digital World's attempts to expel them.
She and DigiDestineds manage to return to the Real World but are persecuted by the people. With Daigo Nishijima's help, the DigiDestined and their partner Digimon hide in their school to avoid the media. She and DigiDestineds try to console Meiko during their stay. The next day, a rampant Meicrackmon confronts Meiko near the school. Jesmon intervenes and his attack results in Meicrackmon digivolving to Raguelmon.
As the situation deteriorates, Homeostasis possesses Kari and warns the DigiDestineds not to interfere. When Jesmon takes Raguelmon to the Digital World, the DigiDestined, their partner Digimon, and Daigo Nishijima pursue them. They arrive in a desert area of the Digital World, where Alphamon joins the fray. Six of the Digimon return to their In-Training forms as a result of Alphamon's attack, leaving only Omnimon, Raguelmon, Alphamon, and Jesmon.
Meiko falls into despair and asks the DigiDestineds to destroy Raguelmon. Tai resolves to carry out her wish despite the objections of the other DigiDestined. During the battle, a fissure opens, Tai and Daigo Nishijima fall from the cliff.
In the aftermath, Raguelmon is incapacitated near Tai's goggles. Kari becomes engulfed in corrupted digital code which causes Nyaromon to digivolve into Ophanimon Falldown Mode, creating a dark portal. As the portal opens, Ophanimon merges with Raguelmon into Ordinemon. The Real World is subsequently covered by a universal blackout, as the invading Digimon become able to move. Afterwards, the Digital World begins to swallow the Real World. Refusing to give up, Matt takes Tai's goggles and rallies his friends.
Believing that Tai is dead, the DigiDestined return to the Real World. She and DigiDestineds fight Ordinemon but are defeated. Hackmon informs them of Homeostasis' intent to reboot all digital technology in the Real World to stop Ordinemon. However, it would cripple all man-made infrastructure. Refusing to give up, Matt and the others have Meiko lure Ordinemon to the sea and confront her again but to no avail.
Guided by Kari's vision, Izzy discovers that memories from all the Digimon have a backup stored inside Meicoomon, which explains why her memories are intact. Meiko unlocks the sealed memories inside Meicoomon, restoring the lost memories and extracting Gatomon from Ordinemon. The reboot of the Real World is halted by Hackmon. However, King Drasil floods Ordinemon with corrupted data. Tai rejoins the others as they reluctantly digivolve their partner Digimon. During the course of the battle, Meiko's Digivice awakens Omnimon's Merciful Mode. Omnimon destroys Ordinemon, deleting Meicoomon in the process. Dark Gennai leaves through a digital distortion after King Drasil's plans are thwarted.
With both worlds restored, Meiko returns to Tottori and Homeostasis shuts down King Drasil. Izzy begins work on a gate that would allow traversal between worlds without D-3s. Three months later on Christmas Eve.