(Katekyo Hitman Reborn) The Storm of the Sky

For some reason, she, Ze Xinyu, gets into a car accident like none before or since (?), and transmigrates to a new world. She thought a car accident would kill her, but instead she unexpectedly arrived in this world. And that's not all: at the same time she arrived in another world, memories belonging to this world were uploaded straight into her brain. She's none other than the younger sister of some useless protagonist from a certain series! In this world, she has a new name: Sawada Xinyu. The female lead doesn't know the plot. This is a Mary Sue story, so proceed with caution if that's not your thing. Theme: