A short and (mostly) sweet yuri series for which you have to crank your suspension of disbelief pretty high, but it's entertaining if you can. The titular Iono is the young Queen of some small nation somewhere who is constantly on the hunt for more young women to bring back to her nation as her concubines; she already has hundreds if not thousands, but her appetites are insatiable. Deciding she doesn't have enough dark-haired beauties in her harem, she visits Japan and is captivated by young Eto; the series follows her pursuit. Iono is a very aggressive suitor indeed.
The series features no men in other than background, and little angst about the characters' homosexuality. There's a certain degree of fanservice, but given the genre, surprisingly little; we always cut away before anything remotely racy is shown, and a lot of things are left implied rather than explicit.
As a short series, there's a little disappointment that there's not more; one gets the feeling of caring about the characters by about the point where the whole thing comes to an end. I was especially left wanting more of Iono's driver and the noodle girl, and other supporting cast.
Within limitations this series is a lot of fun although not all that serious or believable.