The film opens to a wave of comets, shooting across the sky.
Two teenagers, Taki Tachibana and Mitsuha Miyamizu begin to speak, almost simultaneously. They speak of time and of dreams, and how each can be a great loss.
A piece of one comet breaks off and plummets to the earth
We see Mitsuha struggle in her sleep. She calls out to Taki, asking him if he remembers.
Mitsuha wakes up. But it is not her really. It is Taki, who is freaked out to be in a girls body (though not above copping a feel on Mitsuha's breasts). Mitsuhas younger sister Yotsuha comes into her room, noticing her being weird again and tells her breakfast is ready. Taki, as Mitsuha, disrobes and looks in the mirror, freaked out by the strange dream he keeps having; waking up as a girl.
Going downstairs, apparently back to her normal self, Mitsuha eats with, Hitoha, who is their grandmother and guardian. Hitoha and Yotsuha note that Mitsuha had been acting weird the day before. They watch a broadcast that notes that a comet not seen for over a thousand years will be able to be seen in the sky in a months time.
Mitsuha walks to school and meets up with her friends Katsuhiko and Sayaka. As they walk, they see a campaign speech by the local mayor, who is up for reelection. As she walks by, the man screams at Mitsuha to stand up straight. We realize that the mayor is actually Mitsuhas father, estranged from the rest of the family for unknown reasons.
At school, Mitsuha flips through a notebook, and finds a note. It reads, "Who Are You?"
Later, Mitsuha learns that the day before she had forgotten her classroom and where her locker was. This information shocks and surprises her. Sayaka chalks it up to stress Mitsuha is under to perform a Miko ritual for the family shrine, something Mitsuha doesn't want to be reminded of. As the three walk home, they bemoan how small their town of Itomori is; there are no restaurants, bookstores, or social scene. Mitsuha herself dreams of graduating school so she can move to Tokyo.
Katsuhiko suggests they go to a café. The girls scream out excited. In actuality, it is just a vending machine nearby a park bench. Mitsuha goes home, leaving Sayaka with Katsuhiko. Sayaka asks him about his future plans. Katsuhiko says he will most likely just stay in town like he always has after graduation.
Mitsuha, Yotsuha, and Hitoha practice the art of Kumihimo (braid making). Hitoha tells them the importance of what they are creating.
The mayor meets with Katsuhiko's father, who is part of the local construction union, in order to get the support of his men for the upcoming election. Katsuhiko is told by his father that he will work with them the following weekend to his annoyance.
The next night, Mitsuha and Yotsuha perform the ritual for their shrine with includes ritualized dancing and the creation of Kuchikamizake; a sake in which someone chews rice into a paste and spits it back into a bowl, allowing it to ferment into alcohol. A few of Mitsuhas classmates walk by the ritual and mock her, to her annoyance.
As they walk home Yotsuha tells her big sister not to take it so personally, but Mitsuha is losing patience with her life. "I hate this town!" she screams out. "I hate this life! Please make me a handsome Tokyo boy in my next life!"
The next day, Mitsuha wakes up but not as herself. She is in Taki's body. She is quite disturbed to be a boy and all that entails physically. Finding out she has overslept, she quickly gets dressed and heads out, suddenly struck that she is finally walking around Tokyo. Mitsuha (as Taki) arrives to school hours late and is accosted by his friends Shinta and Tsukasa, who note that Taki has been acting weird as well. They suggest going to a café, and Mitsuha readily agrees as there are none where she lives. Getting a call on Taki's phone, she realizes Taki has a job at a restaurant and she is going to be late.
Mitsuha goes to work but being Taki is harder than it looks. She is unprepared to work in a restaurant, making mistakes all night. It finally comes to a head, when a man tries to con the place for free food. Mitsuha is overwhelmed and when the man wants to pick a fight, Taki's older co-worker Ms. Okudera comes over and handles the situation, though the man cuts her skirt with a box cutter out of spite.
Later, Okudera tells Taki that she followed the handbook to handle the situation though she wished she could have done something more severe to the man who was clearly conning the restaurant. Noticing the cut in Ms. Okuderas skirt, Mitsuha offers to fix it. Ms. Okudera is charmed by this, saying Takis has been changing lately, and she is charmed that he now has a feminine side.
The next day, Taki is back to normal and knows nothing of the previous day. The staff he works with wants to know more details with his relationship with Ms. Okudera, but he has no idea what they are talking about. Ms. Okudera comes in and tells them all to have a good day, winking at Taki, which makes him blush.
By this point, Taki and Mitsuha realize their body switching dreams are actually happening, and take steps to help out each other if they switch bodies. Writing notes to each other on their smart phones, and in notebooks, they each set ground rules so they don't step on each others toes. Mitsuhas rules are more concerned with etiquette, not having him taking showers as her (so hell see her naked) and other social cues. Taki gives her tips on his job and tells her not to blow all his hard earned money on sweets, which only makes him have to take more shifts at the restaurant.
Despite trying to play nice, both cant help but have a little fun at the others expense. Taki makes a few people fall in love with Mitsuha at school while Mitsuha flirts with Ms. Okudera, giving Taki a real shot with her. Both of them are livid with the others meddling, both noting that, I dont want a relationship!
One day, Taki switches with Mitsuha on a weekend day. It turns out to be the day Mitsuha, Hitoha, and Yotsuha are traveling to the family shrine far into the forest. While they walk, Hitoha talks to them about the idea of a union; whether it is a braid they created, time itself, or even taking a drink, unions are made every day.
The three make it to the shrine and make an offering of the sake they made during the ritual.
Taki wakes up. Checking his phone, he notices a text from Ms. Okudera, saying she cant wait to meet him. Confused, he checks the notes in his phone, and realized that Mitsuha had set him up on a date with Ms. Okudera.15 minutes from then. Taki quickly gets dressed and races out of his house, racing to meet her.
Meanwhile, Mitsuha gets ready for her day, using her braid to tie up her hair. She realizes Taki and Ms. Okudera are most likely on their date at that moment. She looks into the mirror and sees that she is crying. She is surprised at first but then realizes the truth; she wanted to have that date with Taki herself. Try as she may, she is beginning to fall for a boy she has never met.
Taki meets up with Ms. Okudera and go to a nice, if expensive restaurant. Though they both share a mutual crush, Taki is nervous and unsure how to act. His mind is somewhere else. At one point, they look at a photo display, and Taki is taken by a group of shots that remind him of Mitsuhas town. Ms. Okudera comes up to him and pointedly states she became more attracted to him once he starting acting odd, but he has changed again. He has become someone else. Later, Taki tries to extend the date but Ms. Okudera declines. She notes that is clear that Taki has a crush on someone else; that is why he is acting so different.
Taki, making a decision, tries to call Mitsuha.
Back in Itomori, Mitsuha cuts her hair. She goes to the local town festival with her friends. The comet finally becomes visible, and in a field, Mitsuha stares in awe. She sees a part of the comet break off and fall. Her eyes widen
Back in Tokyo, Taki is sad when the call cannot be connected. He wishes they could switch again, but after that night, it never happened again.
Days pass, and Taki goes through the motions. He begins to sketch Itomori from memory, trying desperately to figure out where she lives, with little luck. One day, he decides to leave the city to find the town and finally meet Mitsuha. Tagging along are Ms. Okudera and Tsukasa, who are there for moral support. They are curious and charmed by Takis mystery girl, while Taki must be coy about how he met her.
The trio travel many places but no one knows the town Taki has drawn. About to give up, Taki and his friends stop at a local restaurant. The owner recognizes the place as Itomori, but when Taki asks how far away it is, the owner goes silent for a moment before explaining three years before the town was destroyed by a comet fragment, killing over 500 people.
Taki is taken to the outskirts of Itomori where he sees little left of the town. He tries to show his friends the notes Mitsuha left for him on his phone, only for them to disappear. He doesnt know what to think.
The trio goes to a local library and sees the reports about the tragedy and the list of the dead. Mitsuha, her sister, and her friends are among the dead. Taki is shocked and heartbroken; he is somehow linked to a dead girl, who died three years ago.
The three get a hotel room for the night. Tsukasa asks Ms. Okuderas opinion on Takis recent behavior and what he claims about Mitsuha. Ms. Okudera, while admitting it is all strange, notes she always found Taki to be nice, but he became even a better person because of this girl.
Later that night, Ms. Okudera and Taki talk. She notices a braid on Takis wrist. Taki says he got a few years ago, but he doesn't remember who gave it to him or why, though he wears it often for good luck.
As he sleeps, Mitsuha calls out to him to remember.
The next morning, Ms. Okudera wakes up to find a note from Taki to tell them to go home without him. He has to go somewhere first.
Taki travels to Itomori, and finds his way to the shrine of Mitsuhas family, still intact. He travels inside and finds the sake Mitsuha and her sister left. Taki thinks if he drinks some of her sake, he can make one last connection and perhaps save her.
Taki drinks some, but as he stands up, he trips and falls. As he does, he takes a journey, and sees all of Mitsuha's life; her birth, happiness with her parents, the birth of her sister, the illness and death of her mother, her fathers abandonment of the family and his duties, her grandmother caring for them, and her death by the comet.
Taki wakes up in Mitsuha's body. He realizes he has one last chance. Seeing the television, he realizes it is the day of the comet, and the towns destruction. Trying to talk to Hitoha, Hitoha realizes that someone else inhabits her granddaughter, as she had a similar phenomenon happen to her when she was younger. Taki wonders if Mitsuhas family line had these connections. Taki (as Mitsuha) tells Hitoha about the comet but is told no one will believe them.
Undeterred, Taki finds Mitsuha's friends Katsuhiko and Sayaka and tell them what will happen. Despite doubting what they have been told, they believe her enough to help. They make a plan to knock out the towns power with explosives taken from Katsuhiko's father's construction company. Sayaka then will get on the emergency broadcast station and tell everyone to evacuate to the school, well out of the blast radius of the comet. However, they will need to convince the mayor, Mitsuhas father, of the severity.
Taki goes to Mitsuha's father, but all the man can see is that his daughter has gone insane and orders her to see a doctor. Enraged, Taki grabs him by the tie and screams, You son of a---but they both stop. Who are you? Mitsuhas father asks, also seeing that his daughter is not standing before him. Nevertheless, the warning falls on deaf ears. Taki, thinking his body with Mitsuha inside is near the Shrine, races up there to meet her.
Meanwhile, Mitsuha wakes up in Taki's body in the present day and sees the town destroyed. Does that mean I died? she asks.
Mitsuha remembers the day she went to Tokyo, hoping to meet Taki, thinking that even though they were technically strangers, if they were to meet, they would know their connection. By chance she met him on the train, though he did not recognize her (as their connection would only begin 3 years after her death). Heartbroken, she leaves the train, but Taki senses something and calls out to her. She takes out her braid and flings it to him, asking him to remember her name. She was the one who gave him the braid and thus linked them together.
Taki and Mitsuha finally are at the shrine, but cannot see each other, being separated by time itself. However, during the Magic Hour in a certain spot, they can finally see each other, and meet for the first time. Taki returns her braid and she ties up her hair. Taki suggests they write each other names on their hands so they wont forget. Taki writes his, but when she goes to write her name, the connection is broken.
Taki wakes up, back in his body, on the outskirts of the still destroyed Itomori. He cannot remember why he came there, or the name of a girl that haunts him. He heads home to Tokyo.
Back in the past, Mitsuha, knowing what will happen enacts her plan with her friends. They blow up the power grid with explosives, switching on emergency power. Sayaka then tells the entire town of forest fires in an effort to get people to the school. Though some take heed of the warning, not enough people do. Plus, the Mayor is trying to figure out who is sending out this false warning. Eventually, Sayaka is caught and the warning is turned off. Katsuhiko tells Mitsuha that unless she is able to convince her father, everything is lost.
Mitsuha begins to run, but becomes increasingly despondent as she cannot remember Takis name. She trips and falls, looking at her hand. She sees that Taki, instead of writing his name, wrote I LOVE YOU instead. Shocked and in tears, she continues to run, before reuniting with her father in a building.
The comet fragment still hits the town, destroying it.
5 years later...
Taki has graduated from high school and college, and is now trying to enter the work force as an architect. However, his passionate and idealistic views on preserving cities in case of disasters make him look foolish to interviewers, which lead him to get few if any offers.
Taki gets a call from Ms. Okudera, asking to meet up. They catch up, and she mentions they day they went to Itomori. Taki says he doesnt remember much of that day or why he was momentarily obsessed with the town. It turns out that reality has changed. Mitsuha was able to convince her father of the danger. That on top of her daring plan, led to the entire town to be evacuated to an area outside of the blast radius. The town was decimated, yet no one died. Still, Taki has no idea of his connection to averting a tragedy or the girl he help save.
As they part, Ms. Okudera tells Taki that she hopes he one day finds happiness. Taki notes the same, though it has felt as if he has spent years searching for it, yearning for something, or rather someone.
In a diner, he hears a couple bicker over wedding plans. We see it is Sayaka and Katsuhiko, who survived thanks to Taki and Mitsuha. Taki feels a momentary feeling of connection, but brushes it off as nothing.
Taki, not knowing why fully, searches the streets every day for a woman whose hair is tied up with a specific braid.
At one point, Taki and Mitsuha cross paths in the street, but dont look back, deciding their weird feelings are nothing.
One day, finally, they see each other on different subways. Though they are not sure why, they feel a connection. After getting off, they scramble around the city, searching for each other. Taki sees a woman at the top of a staircase and passes her by, as she walks down. Once again, they feel a stirring and almost ignore it once more. However, Taki cannot take it anymore and calls out to the woman. It is Mitsuha. He asks if they have met before. Mitsuha looks at him with tears in her eyes. She says that she feels the same way. Simultaneously, they ask, "Can I ask you your name?"
We are left to infer they will recover their memories and finally be together, in love.