Bukbu Gongjangnimeul Yuhokagetseumnida

Rinha, Korea's most beloved actress, gets into an accident while on set. When she regains consciousness, she realizes she has traveled to the Kingdom of Iklein and meets the northern duke Calcion, who saves her from a demonic beast. Calcion asks her to be his fake lover so she can get into socialite and discover the conspiracy happening in his castle.
(Source: WEBTOON)