About Ballroom e Youkoso manga:

An ordinary middle school student, Fujita Tatara couldn’t find any objective in life and spent his days idly.
One day, a group of delinquents picks a fight with him and he is saved by a mysterious man.

After that, the man surprisingly takes him to a ballroom dancing class. While being inspired by a girl dancer who goes to that school, Hanaoka Shizuku, and her partner, a genius dancer, Hyoudou Kiyoharu, Tatara starts dedicating his youth to dancesport.