Botonghakgyo

Geum Ta-Rae applied for the all-boys "Ordinary School" to achieve his childhood dream of conquering the world. His twin sister, Geum Na-Rae, is absolutely to his admission. However, after Ta-Rae got into an accident, Na-Rae disguised herself as her younger brother and entered the school as he had wished.

(Source: Daewon C.I., translated)