Despite its somewhat cheery and innocuous title, Chronicles of the Hidden World, subtitled How I Became a Doctor for the Gods, is a fairly dark story. Its protagonist/narrator Yae is reborn from our world into one that greatly resembles Ancient Japan with more of a fantasy bent: almost everyone is born with a Nature, a specific category of spiritual energy, most people are “elebeasts” and have an animal trait or two, and things like fallen gods are very real and very dangerous. Yae is what's known as an “uroko,” a person whose soul has migrated from our world and been “reborn,” although that word is less than perfect since most uroko appear as toddlers in the hollows of trees. While many uroko have some memories of their past lives, most forget them as they grow. Yae is not one of them.

Retaining all of her memories of life in modern Japan (barring her death in her twenties, something that bothers her from time to time), Yae is very much not like the other uroko – or other girls, for that matter, although not in a YA fiction special snowflake kind of way. Because she has those memories, Yae acts older than her physical age, but she also still has many of the attitudes of a modern person, and the most significant among those is a lack of the sort of superstition that drives the way everyone acts in her new life. While Yae knows that in Izumo fallen gods, corpse bugs, and other terrible supernatural things very much exist and are dangerous, she retains a skepticism that sets her apart from everyone else, and that more than anything is what sets her on her particular path.

It also may relate to her being “Natureless,” something that throws most of the other characters in the story off. Almost everyone in Izumo has something called a Nature, which is basically a particular type of spiritual energy that informs their personality and demeanor. Yae lacks this, and that makes a lot of people very uncomfortable. Although it isn't spelled out, there's a very strong implication that her Natureless state could come from the same roots that allow her to work closely with people who have become corrupted and are in a state of monstrous transformation: she simply doesn't believe that it's real on a soul-deep level. It's a welcome change in an isekai story from the usual broken stats and application of “real world” knowledge to a fantasy setting, and it's something that Yae herself feels a bit conflicted about – a part of her really does just want to belong and live her life, but something within her keeps refusing to allow that to happen. She is, in many ways, her own worst enemy.

Luckily for Yae, she does have the requisite gang of hot guys by her side, although “gang” is overstating it. As the de facto priestess for her tiny province (everything is on a smaller scale in Izumo, with the exception of objects from our world that wash up there; “mysteriums” are many times larger to the point where Yae lives in a discarded Coke can), Yae encounters a mostly-spirit tiger. She later learns that he was a god from Japan who, along with his sibling gods, somehow ended up in Izumo, where events led to his corruption. When Yae cleanses his soul, he becomes “hers” in ways that he can't (or declines to) fully explain, and after Yae does the same for his brother, Arai and Sui become her semi-devoted companions. The brothers, who can switch between human and tiger forms, are the ones who guide Yae into god-doctorhood, and in many ways can be said to be the ones who help her t find a purpose in Izumo. There are clear hints that romantic subplots will be brewing as well, mostly with Arai, but there are a few reverse harem possibilities raised by the story with both Sui and some of the other men Yae encounters.

There's a grimness to the world that's in part based on the corrupting forces at work in Izumo, but it's also partly due to Yae's own feelings about her entire situation. It also takes a while for the story to really get going, so although this is a short novel (under two hundred pages), it's not a fast-moving one, which works for the plot but may not for all readers. But the translation is smooth and Izumi's illustrations are very pretty, while Tamaki Itomori's world-building is substantially different from what we more typically see in the isekai genre. If you have the patience to wait for the story to unfold, this is a fascinating book, and watching it unfold in subsequent volumes should be an interesting reading experience.