When Masamune Makabe was a child, he was rejected by a rich, beautiful girl named Aki Adagaki, who gave him the nickname "Piggy" for being overweight. Devastated, Masamune put great effort into working out to improve his appearance. Now a handsome yet narcissistic high school student, Masamune is determined to exact revenge—he will have Aki fall madly in love with him and ultimately reject her the next time they meet. To his surprise, Masamune discovers he has transferred into Aki's school. Setting his plan into motion, Masamune first begins to form a relationship with the "Brutal Princess" but, despite his efforts, fails miserably at his initial attempts. Shockingly, when Masamune finally progresses towards his vengeance, he receives a mysterious letter addressing him by his old nickname. Unless Masamune discovers the sender's identity, his plan is doomed before it even starts!

With the tumultuous cultural festival behind him, Masamune Makabe continues his efforts to carry out his revenge: to make the "Cruel Princess" Aki Adagaki deeply fall for him and then immediately dump her. As his class is going on a trip to Paris, widely known as the City of Love, Masamune has the perfect opportunity to get even for his childhood heartbreak. Before Masamune can impress Aki, the two meet Muriel Besson, a French high school otaku who aspires to create a romantic comedy manga series. Muriel believes Masamune is the ideal model for the protagonist and asks for his help. The boy reluctantly agrees, dragging Aki along to provide inspiration for the love interest's character. But to do so, the two must show Muriel what Japanese love is like. To make matters more complicated, Kanetsugu Gasou is masquerading as Aki's childhood friend, Masamune, to trick and use her. With mix-ups and love rivals galore, Masamune's revenge is proving to be quite the difficult task.