It's going to be crazy now. My sister's trap

Since childhood, Saori (Kurugi) has continued to feel inferior to her older sister Ayaka (Orikasa), who is well-looking, has a good personality and is liked by everyone. Now that he lives apart from his sister, his life is rough, and he lives a self-deprecating life with Katsu, who lives together as he goes along. One day, when Saori receives news of her engagement from Ayaka, she becomes furious at the difference in her situation with her, and turns that twisted blade of emotions towards Ayaka...