Amelia is a plain girl who is Sophie's fan and follower. One day, she sees Marion, Sophie's fiance, with Rozetta, another girl. "I wonder if His Highness will look at me more if I earn Rozetta's ire..." To prevent Sophie from becoming the antagonist, Amelia begins to coach Sophie in love. However, this attracts the attention of Sophie's tsundere brother?!

Once an OL (Office Lady) around 30 and born with memories of her past life, when Tsubaki was around 4 years old, from the words of her half-sister who she also thought held memories of her past life, she recalled that this world was from an otome game. In the game, the half-sister born from a lover was the heroine, and she was the villainess noble girl who tormented her. Furthermore, the END always concluded with a suicide. But in this world, there were a lot of differences in the setting. Thinking that she might be able to save her mother who commits suicide, it's a story where she does her best in protecting her mother and the main capture target character, her cousin, from her half-sister's devil like clutches.