ONE: High School Heroes - S01E02 - ONE: High School Heroes 1-2

A romantic comedy which is about a timpanist witnessing a murder case but cannot remember anything about what happened. With the help from a mysterious guy, she attempts to recover her memories from that day.

Cellphone app Joalarm is created. If someone likes you and they are within 10 meters of you, the alarm for the app rings. The app also shows how many people like you, but the app doesn't reveal specific details on who likes you.

Kim Jo-Jo (Kim So-Hyun) is a high school student. She is pretty and smart. She seems like cheerful person, but her parents died when she was young. Since the death of her parents, Kim Jo-Jo has lived with aunt's family. Living there is not easy for Kim Jo-Jo. She doesn't download the app Joalarm.

Meanwhile, Hwang Sun-O is a popular male student at the same high school where Kim Jo-Jo attends. He is the son of a wealthy family, but he is not loved by his parents. His best friend Lee Hye-Young also attends the same high school. Hwang Sun-O notices that his best friend Lee Hye-Young likes Kim Jo-Jo. Hwang Sun-O wants to know if his friend really likes her, so he kisses her.

People think it is a doctor’s bounden duty to save a patient’s life. But things are different now. Things are needed to be considered other than saving one’s life. Modern medicine has been developed remarkably, and it is quite possible to save a person's life who is on the verge of death. But we need to think about if prolonging a patient’s life makes the patient truly happy. Cha Yo Han is a promising doctor who needs only 10 seconds to figure out a patient’s condition. While he is gaining his fame with his outstanding skills, he confronts one patient who changes his whole life. Kang Si Young is a doctor with a warm heart. Her family has been doctors for generations. She takes after her mother’s exceptional talent and her father’s high empathic ability. But one day, she suddenly leaves the hospital. After a year later, she goes to the penitentiary to serve as a temporary medical doctor, and she meets a prisoner who was a former doctor. He is a genius who can grasp the patient’s condition within 10 seconds. After meeting him, Si Young’s life totally changes. And the day she comes back to the hospital, she meets the prisoner again, and this time, he is a professor. Doctor John is a human medical drama of anesthetists who seek the cause of mysterious pain their patients suffer, like detectives chasing after a suspect.