Swimmer's Paradise (Free! FanFic)

This is a story about a student at Iwatobi High School (Rin Matsuoka) who has kind of had a "thing" for his rival (Haruka Nanase). He hasn't seen him in over 5 years, and Rin sees that he has changed both in size and appearance. Basically, he thinks he has changed completely. But, as soon as he sees that Haru has enrolled in his school and is now sitting next to him, his feelings towards Haru is not one of rivalry but of caring and...love. ;)
As he starts to notice his feelings, he starts to get confused with his emotions, not noticing what is truly happening with Haru.