Friendly Rivalry - S01E04 - Friendly Rivalry 1-4

Watcher mengisahkan seorang detektif elite yang membentuk kelompok detektif untuk dalam negeri yang memberantas kasus-kasus korupsi di negara tersebut.

Dirinya merupakan orang yang sangat bijak dan cerdas. Ia pun memutuskan dirinya untuk jadi pemimpin di kelompok detektif tersebut.

Diperjalananya, ia menemui berbagai orang dengan berbagai latar belakang dan permasalahan, seperti seorang pengacara yang dipecat dan berhenti karena terjerat sebuah kasus.

Lalu perwira polisi yang dipecat dan keluar karena sebuah kisah perselingkuhan yang dialami dan mereka pun bergabung dalam kelompok detektif tersebut

Lee Jae-Sang (Rain) is a lawyer at JK Law Firm, which is one of the biggest law firms in South Korea. He is an excellent lawyer, but he only cares about winning for his benefit. One day, he has a mysterious car accident and he is drawn into a parallel world. There, Lee Jae-Sang finds himself working as a prosecutor. He is strict in carrying out the law. He is married to Ra Shi-On (Lim Ji-Yeon), who loves Lee Jae-Sang and is faithful to him. In the world where Lee Jae-Sang came from, he broke up with Ra Shi-On ten years earlier and Ra Shi-On works as a detective. Lee Jae-Sang struggles to cope with his different selves.

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.

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.