Moon Lovers: Scarlet Heart Ryeo 月之恋人 (Vol.1-20 End)

Synopsis:

During a total eclipse of the sun, a 25-year-old 21st century woman, Go Ha-jin (Lee Ji-eun), is transported back in time to Goryeo Dynasty. She wakes up in the year 941, in the body of Hae Soo and there, she encounters the many royal princes of the ruling Wang family. She initially falls in love with the gentle and warm 8th Prince Wang Wook (Kang Ha-neul), and later Wang So (Lee Joon-gi), the fearsome 4th Prince who hides his face behind a mask and is given the derogatory label "wolf dog". Meanwhile, rivalry and politics ensue among the princes, in a fight for the throne, as Hae Soo finds herself unwittingly caught between it all.