I am well aware I am ridiculously late to the party on this one. Still, finally got to it.
Mitsuha is a country girl, living a quiet life in a quiet town in the quiet mountains, (not their official name), who wants nothing more than to get to Tokyo. Taki is a city boy, living a city life in the city Tokyo (actually the official name).
One day, they wake up in each other's bodies.
No small amount of boob (and probably other body part) grabbing later, they realise that this is both cool (new experiences they would otherwise never have) and utterly disastrous, since neither of them know how to behave in the other's life. Mitsuha's carefully ordered precise life as a shrine maiden clashes with Taki's chaotic job-filled evenings. But, mostly fun and games.
They communicate with each other via written messages, leaving notes and a diary of the previous day so that they don't find themselves in situations they're not prepared for. Taki helps Mitsuha out with her social mobility problem (being the Mayor's daughter is a bit limiting), and Mitsuha is the ultimate wingwoman, able to do all the hard work of flirting with people for Taki.
Of course, you can't spend that long inside someone without something coming about, and the film tells of their romance and occasional missed connections. About half and half romance and fantasy (although body switching might be science fiction - take your pick).
It's a beautiful film. The wide "shots" are dramatic and full of detail, with the gentle nature scenes contrasting sharply with the busy but precise cityscapes. The "cast" look more fluid than the usual, and have very expressive faces. A lot of work has gone in to making this special, though there's a mid-film sequence that really pushes the boat out - you'll know it when you see it. It also manages to make the "rapid fast forward" effect look natural, which was cool.
It's a twisty tale, with a fair few moments that I had no way of predicting. Certain elements fall into obvious tropes, but there were frequent surprises, and a lot of things that I didn't see coming. It's mostly cheerful, with the supporting characters an excellent source of light relief, though it's also generally a jolly film.
The usual body switch problems are all present but pleasingly done in montage form, giving you the best of both worlds - getting all the jokes, but allowing more film time for the emotionally powerful plot. It also has a few nicely subtle hints throughout that a second watch will let you pick up on.
All in all, a joy to watch, and probably one that will get another re-watch sometime soon.