The First Book of "Rain Falls Jiangnan"

Who will win the twin daughters [Twin heroines, green tea, white lotus, no male protagonist, group favorite] Gu Ranran has been held in the palm of her parents' hands since she was a child, but one day she was told that she has a biological sister? It doesn't matter. I have a system for defeating my brother. Let's see how you can beat me. Gu Qingqing has been looking for the Gu family since she was reborn, but she was told that she has a sister? I thought she was the group favorite, but it looks like I have to fight against my sister. I am professional in conquering my brother.