The story is based on Cinderella. Instead of Cinderella losing her glass slipper, Hitsugaya lost the love for his brother. Instead of the prince giving Cinderella the glass slipper, Hitsugaya went back to the ball when it ended and started to love his brother, but he didn’t want to admit it. That’s why Hitsugaya always says that he hates his brother.
No matter how much you hate someone, you’ll soon love them. :)