your name AU! Saruhiko as Taki and Misaki as Mitsuha :D
I did this one the other way around before, so reverse scenario. Say Yata’s living in this small backwoods town, he lives with his mom and little siblings near a shrine and often works there (ooh, and maybe his bio-dad is actually the town mayor, Yata’s sort of angry at him for leaving Yata’s mom but also really wants to talk with him too and is increasingly upset that his dad always ignores him or acts like he’s causing trouble if Yata tries to talk with him during public events). Yata always feels really restrained in the town, like his personality is big and boisterous in a very slow moving town and he’s a bit isolated because of it, almost everyone at school constantly teases him and he gets in fights all the time, his only friend Kamamoto is always having to hold Yata back from beating people up because they made fun of him for working at the shrine. Then one day when Yata comes to school and someone tries to bully him into getting into a fight again Yata just glares coldly at the guy and clicks his tongue before turning and walking away. The bully tries to grab Yata and Yata yells at the guy not to touch him, looking so fierce that the guy just stops dead and lets him go. Then on top of that the usually not too bright Yata is suddenly answering any question the teachers throw at him with ease and Kamamoto’s super worried, especially since Yata starts calling him ‘fatty’ and telling him to go away. The next day Yata has no idea about any of this and is super confused as to why everyone is staring at him like that.
Meanwhile Fushimi’s living on his own in Tokyo, having run away from his abusive home life. He’s always isolated at school even though a couple of his upperclassmen, Akiyama and Hidaka, are always trying to befriend him and his annoying work senior Munakata keeps trying to be a mentor figure for him. One day Fushimi too starts acting strange, accepting Akiyama and Hidaka’s invitation to eat lunch together on the roof and even going out with them to a cafe afterward, all excited about the parfait he gets, and then running in late to work. Also while at work though he doesn’t quite appreciate Munakata – actually he thinks that guy’s kinda creepy, especially the way he keeps giving Fushimi this oddly knowing stare – he’s at least more open than normal. The next day Fushimi wakes up with no memory of the day before but when he checks his phone someone’s filled in a whole section of his diary app, the entry is riddled with typos and emoticons and Fushimi wonders if like a twelve year old girl named Misaki got a hold of it. He’s also not pleased when Akiyama, Hidaka and Munakata all act extra friendly to him the next day and is super confused as to why they all seem to think he’s their friend all of a sudden.
So eventually Yata and Fushimi realize that the body switch is happening, Yata leaves notes in Fushimi’s phone and Fushimi writes whole notebooks full of complaints about Yata’s life, Yata’s family, Yata’s friend, Yata’s school, Yata’s body, pretty much everything. Yata decides that whoever this Fushimi guy is he sure seems like a jerk and at first they’re both pretty hostile to each other, Yata leaves mocking notes in Fushimi’s phone and enjoys taking pictures of himself with his new friends Akiyama and Hidaka so Fushimi can wake up to a new phone wallpaper of the three of them taking a selfie with a giraffe at the zoo or whatever. Fushimi in retaliation has been known to tell everyone at Yata’s school to call him Misaki and writes the word ‘idiot’ across his forehead in big letters before going to sleep. But then slowly they start to warm up to each other, like maybe Yata switches into Fushimi’s body when Fushimi’s a bit sick and leaves him soup and notes as to how to treat the cold. Fushimi sees Yata’s nervous about upcoming exams and takes copious notes on his behalf, Yata’s so relieved he leaves Fushimi like his favorite local chocolate on the desk to have when he next switches bodies. Meanwhile the bodyswitch is good for both of them, Fushimi’s able to get people at school to stop bullying Yata and to appreciate Yata’s open nature more while Yata’s able to make it easier for Fushimi to suddenly make friends.
Then one day the bodyswitches stop and while Fushimi acts like it’s a relief he’s actually really worried. Imagine he goes searching for Yata too and when he finds out about the freak meteor accident that killed Yata years ago he just freezes up for a moment, like here’s another precious thing lost and he didn’t even realize it was precious until now. Then he starts forgetting Yata’s name but he knows he’s losing something, knows that if he does nothing it will all fade away, and that’s what gets him to go try and find a way to switch bodies with Yata one more time, wanting to save Yata’s life so they can finally meet face to face because Yata’s the first person who ever made Fushimi feel like there was someone in the world who truly cared about him.