Summary Saver from Kainu Manga
Saver summary: Lena Ha is a beautiful and tough girl who is the captain of the kendo team. She meets Hye-Min Kang, the son of the president of a large company in Korea, and the two seem to feel love at first sight. But when Lena learns that she and Hye-Min are half-siblings, a string of unfortunate occurrences lead to terrible consequences. Lena tries to do everything she can to prevent them, but she ends up falling in a strange body of water in result. When Lena awakes, she finds herself in a strange kingdom...and learns that she may be its only hope. Left with few options, Lena is forced to disguise herself as a man. She must face many challenges and experience more than she ever would have expected. Adventure is on the forecast.
