If I understand where this book fits in with the other two in the series, it is roughly book 1.5. I've read book 2, but not book 1, and I don't think this one truly works without having read the first one (it might be that it wouldn't have worked anyway, but it felt like reading fanfic of a series that I wasn't yet familiar with the characters for). It reads almost as an out-take, although it might be that it is an alternate viewpoint on a set of the events -- I'll leave that judgement for later. 

I don't really have much to say. There is a little bit of background for the viewpoint character, some obsession about how falling in love is out of character for them, and some actual communication after failure to communicate causes issues.