Here is a summary from the Seven Seas website:
Tsukina is a single, thirty-something office worker whose favorite thing is curling up with a good book. When a god tells her that she must go to another world to become its magical savior, Tsukina isn’t interested. She has zero desire to go on some grand hero’s journey. So when she arrives in this strange new land, she decides to use her magical powers to create a cozy little book café instead. Her first customer is a handsome soldier who loves reading almost as much as she does. But when a fellow “savior” starts causing trouble, Tsukina might have to play the hero after all!
I picked up the first volume in this series on a whim. I saw it at Barnes and Noble last summer, and it is such a charming story! I haven't read many manga like this. It's based on a light novel, which, from what I can gather from Wikipedia, is a fluffy serialized story aimed at teens. Maybe the equivalent would be a magical Sweet Valley High series. (Are series like this still popular in the US? I can't think of any new fluffy teen series from my time as a Youth Services library aide. Things seem to have shifted to dystopian series.) There are plot threads that run through all the volumes, but each volume also has its own story.
If light novels and manga like this are mostly fluffy romance, and if the fantasy stories have a Chosen One protagonist like much of the popular YA in the US in recent years, then this novel seems to upend some of those tropes. The romance between Tsukina and Ill is very straightforward and kind of boring. They bond over the fact that he is a total bookworm like her. After he is done with his duties as a knight of the country, he likes to just sit and read. And while it is boring, it's also very sweet and fluffy. There are some moments of drama, when Tsukina has to step up and use her magic to be a Savior, but then she goes right back to her magic bookstore-cafe-house and cooks some soup and reads a book.
The world building is what is most appealing for me. While I am a leeeeetle bit older than my mid-thirties, I would absolutely take Tsukina's deal. She very cleverly asks for a tutorial on how to use her magic from the god that gives it to her, and she makes sure right away to set herself up for practical things. And yes, she finds herself in occasional peril, but who among us hasn't? I'd much rather face one of the wolves that she faces at some point than deal with my boss, not just because I could use my magic to kill the monster. I wouldn't even mind a handsome if slightly dull husband (although I'd probably choose his best friend -- he's a bit more lively).
All in all, I will definitely keep reading this series. It's pure fluff and a nice way to pass a half hour or so.