Dressed as the Regent's Favorite Concubine

Freshman Lu Liyang went to a new school, but unexpectedly fell asleep on the high-speed train. When I wake up, everything has changed. What? She has a twin sister? What? My sister is still a concubine in Beiqin Palace? What? My sister is pretending to be a concubine, but she is actually a killer?! ... Does this plot sound a bit familiar? Suddenly one day. "Sister, run away." Wait wait... This plot is wrong! Why should she be given away? Isn't she a sister? ! What? For a great cause? Go to hell, if you don't run away now, you won't wait until later! !