The story is set in the 19th century, in a rural village. As the description says, this is a story about Amir (it's spelled like that in the book, might be a translation difference), a 20 year old woman from a nomadic tribe marrying Karluk, a 12 year old boy from another village. In their society this is considered to be somewhat unusual because she is too old. Normally she'd have married at 15.
The story is mostly of the "slice of life" kind, and so is quite thin on plot. That's not necessarily a bad thing, but don't expect a whole lot of development in here. Quite a lot of it goes on detailing the lives of the characters, and the cultural differences between Amir's and Karluk's villages. There is some romantic content, though more than romantic I'd describe it as "cute" for lack of a better word. People who are interested in learning how other people lived will probably find this interesting. People who expect a lot of action and plot development should look elsewhere, though.
For people who feel uncomfortable with the main characters, I'll say that nothing happens between them in this book, though I expect later ones to contain something. In the context of this story and the society that is depicted, Amir is considered to be a bit old, and to have limited child bearing years, so she'll probably be expected to have one soon.
A somewhat odd thing is that one of the characters in the book seems to be some kind of modern historian. In this book his presence is unexplained and seems to be entirely unnecessary. He doesn't appear a whole lot though, so it's not a big deal in any case.
The artwork is extremely impressive. It is very detailed and enjoyable to look at. The content inside really does look like the cover, except for being in black and white. I'd say the book is quite worth buying just to look at the artwork. Kaoru Mori spent a lot of effort on drawing very detailed clothing, scenery, rugs and pretty much everything else. It is much better drawn than any other manga I've seen so far. The pages that start each chapter are especially detailed, and would do very nicely as a desktop background.
The book itself is hardcover, well made and with a very nice dust jacket. The publisher definitely took good care to make sure the quality of the book matched that of the content.
Overall, I'd say that this is well done, enjoyable and well worth the money.