After I Transmigrated into a Book, I Helped the Second Male Lead Win

After Zhou Xin'er dies, she is bound to System 317 and transmigrates into the body of the heroine of a novel with the same name. 317 says, “Host, your mission is to win over the second male lead and make him the male lead...” She thinks she has completed the mission, only for the stupid System to tell her there is more than one world???