This is a continuation of my first story, Hatsukoi, so if you haven't read that, you probably won't understand what's going on.
Disclaimer: I do not own Bleach or any of its characters. I only own my own characters and ideas.
Almost 10 years have passed since Hitsugaya and Karin parted, so let me fill you in on what, in my mind, happened in the mean time. In the final war with Aizen, Hitsugaya, in his urge to avenge Hinamori, defeated Aizen himself in single combat. His courage and skill was recognized throughout Soul Society, to the point where Yamamoto soutaicho wondered who was really the stronger shinigami. Kuchiki Rukia was given an almost permanent assignment in Karakura town. She spent every other month rotating between Karakura and Soul Society. During her stays in Karakura she lives with the Kurosakis as a third daughter. Karin and Yuzu call her oneesan and Isshin constantly pesters Ichigo about when he is going to propose. Ichigo, having missed so much school due to his adventures as a shinigami, failed his college entrance exams. Deciding that sword fighting was the only thing he was really good at anyway, he opened a kendo dojo and, with Rukia's help, was training several decent fighters. This left the future of the Kurosaki clinic to Karin and Yuzu, who are currently in their final year at Karakura Medical College. Karin, after her interactions with the shinigami, decided that kendo was a worthwhile skill for her to have. She was so dedicated and talented that she became a national kendo champion while still in high school.
And then there was Kentaro. Confident and cocky, he wasted no time in challenging Japan's female kendo champion (aka Karin) to a bout when they met at the kendo club on the first day of medical school. He swiftly lost five times in a row, but refused to admit defeat. Karin wouldn't have thought of him as anything more than a warm up, but when he beat her resoundedly at soccer the next day, she gained some respect for him. The two quickly became friends. Best friends in fact, each providing a challenge for the other. And this is where our story resumes.