After being humiliated by Aki Adagaki as a child, Masamune Makabe undergoes a stunning transformation from an overweight boy into a handsome, self-absorbed high school student. Obsessed with revenge, Masamune aims to make Aki fall for him only to reject her in return. When fate brings Masamune to Aki's school, he seizes the opportunity to execute his plan. Despite his initial failures to win over the 'Brutal Princess,' Masamune is thrown off course when an anonymous letter referencing his old nickname threatens to derail his schemes. To succeed, Masamune must unravel the mystery behind the letter before his elaborate revenge plot is jeopardized.