The very greatest Zutara story you will ever read. The author actually had to come out and state, several times, that she has never written for the show, because a lot of people really couldn't tell the difference. It's also notable for completely averting the usual cheap plots people come up with to pair these two off quickly, allowing their relationship to develop naturally (although it does make mention of them
, usually in the form of theories the other characters have as to why they got together). Worth checking out.