This is #5.1 in the Supernatural Consultant series. However I haven't read any of the other books in the series and I didn't find that the story suffered any for a lack of knowledge.
This is a short, cute read. It took me less than half an hour to read. It's sweet, as befitting a tale where the MCs are both 15.
And really there is little more that can be said without giving the story away.