일제강점기인 1930년대, 독립운동 단체는 분열과 갈등을 거듭하고 독립운동 세력을 분열시키려는 일본의 계략은 더욱 악랄하고 잔인한 시기였다. 무장 투쟁 단체 '의열단'을 이끄는 김원봉은 일본 경찰에 운동가를 밀고하려던 옛 동료를 저격한다. 일본 경찰은 죽어가는 그에게서 임시 정부의 비밀 요원이 조선인 여성 의사라는 정보를 얻는다. 이영진은 그 말을 듣고 자신이 의심받을까 걱정한다. 일본인 양아버지의 후원으로 조선 최초의 여성 외과의가 된 주인공이기 때문이었다. 한편 배신자를 죽이는 데 실패한 김원봉은 일을 마무리하기 위해 병원에 잠입하고, 그곳에서 이영진과 운명적인 만남을 가진다.
During the Japanese colonial period, two events paved the way for the independence of Korea, the March 1st Movement and the establishment of the Provisional Government of the Republic of Korea. And with it, a covert armament for freedom was born, the Heroic Corps. The man leading the corps goes by the name of Won Bong, his real name only a few people know. He rarely stays in one area for more than two hours and sleeps for only short periods at a time. With fiery passion in his heart, he moves about swiftly and dreams for his country's independence. Young Jin, a Korean woman raised by a Japanese military doctor, follows in her surrogate father's footsteps, and through a series of events, attends a prestigious medical university in Shanghai. She returns to Joseon and becomes the first female surgeon. The two of them cross paths, and although they follow different ideologies, Won Bong soon realizes his need for her and begins to regret sending her deep into enemy territory.