This work from flanvia is quite different from their stories seen in commercial magazines, as the cover implies, so if happy, lighthearted vanilla stories are what you're looking for it's best to stick to flanvia's other work. Anyway, the doujin summary above does a pretty good job of summing things up. I will add that Yuuko gets loaned out to some older men as well, and the ending is not a happy one. The art in this doujin is great, and while the female protagonist, Yuuko, is "plain-looking", flanvia draws her so succulently, and that really enhances her role in the story. flanvia also does an exquisite job with her facial expressions, adding a greater sense of erotic depravity during the sex scenes. The sex scenes, while not extremely hardcore, are still pretty depraved and are portrayed in a very erotic manner and show how submissive Yuuko is. All in all, if you're into messed up situations then I really recommend this doujin. It's also a fairly long one too, and I really enjoyed reading it.
Key is easily one of my favorite ero manga authors. I love their art and their stories are very engaging, and the ones collected in this book are fantastic. It's also great to have the sequel chapter to the "LOVERS" story in this book, which is titled "Turn." Key's girls are sexy and Key does a magnificent job in conveying lust in their stories.