What you're holding in your hands right now, assuming you aren't viewing a preview online, is more or less a sequel to Eric Meyer on CSS, which was published in 2002 to fairly resounding acclaim. The project-based approach drew high marks, and it seems that a lot of people liked the feeling of being able to watch over my shoulder as I worked through the projects. That was exactly the feeling I aimed to provide, and I've endeavored to create the same feeling with this book.
So, if you do buy this book and you like it, you can get more of the same in Eric Meyer on CSS. On the other hand, it's important to note that you don't have to own Eric Meyer on CSS to use and enjoy this book. Each stands on its own as a self-contained, independent work. So don't be afraid that you won't be able to understand what the characters in this book are doing because you never read the first one. I don't have any characters.
There is a plot, though (actually, two of them). The first plot describes a journey of learning and experimentation, wherein our hero (that's you) follows the path of an experienced guide and learns the ways of a new and wondrous land. The second plot (kind of a subplot) is an underhanded attempt to lure you into using more CSS by tempting you with design flexibility, improved accessibility, reduced page weight, and cool visual effects.