Clannad - Season 0 Episode 2

In an alternative timeline where Tomoya and Tomoyo are dating, Tomoyo becomes student council president, but bad rumors start around the school due to Tomoya's bad reputation. Tomoyo becomes busy during the school festival, and continues to be so while she attempts to save the sakura trees in town. Tomoya realizes that he is holding Tomoyo back from greater things, and despite both sides being reluctant, they break up. Time passes as Tomoyo's reputation builds and Tomoya and Youhei watch on the side through her many accomplishments, one of them being ultimately saving the sakura trees by the winter. At that time, Tomoya and Tomoyo meet and talk for the first time in months and they decide to become a couple again.