They All Traveled Through Time, so Why Is My Brother the Emperor?

[Book-traveling + system + sister-sister double-traveling + tyrant system + rescuing the villain] Su Jian accidentally slipped into a novel she had read When others wear books, they are either queens or princesses, but she is dressed as a palace maid. Still the kind of person who is sentenced to death as soon as he wakes up! With sadness rising, Su Jian felt something was wrong Why does the emperor's child above his head look so much like his brother! ? Gan! They were all wearing books, so why did her brother dress up as an emperor? Why? !