The core theme of both stories is the same: The female protagonist possesses a vibrant personality and relies on her intelligence to survive. In different scenarios, she assumes the role of a close relative of the strict male lead. Initially, they have a competitive relationship, but gradually they develop feelings for one another. Furthermore, a second male character, an apparently perfect individual, appears as a supporting lead in both storylines.
One is modern day and the other wuxia, but in both the FL is brought into the ML's house to impersonate his sister who she looks exactly alike. The ML either knows from the start or guesses very early that she isn't his sister, and the real sister in both dies in the first episode. Both MLs start out threatening to the FL but then soften and fall in love with her.
