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.
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.
Ki Moo-Hyeok, a lawyer with a high winning rate, only cares about money. Due to a murder case at a high school which he deals with, his reputation as a lawyer hits rock bottom. To regain his good name as a lawyer, he sneaks into the high school and work as a temporary teacher. He tries to reveal a secret which the students have, and gets involved with Teacher Ha So-Hyun, a P.E. teacher who loves her students. They then face the students'secret.
Mo Seok-hee is an only child and her father runs the large company MC Group. She is beautiful, smart and rich. Mo Seok-hee appears like she is arrogant, but she struggles over her mother’s death. Her mother was killed 15 years ago. Meanwhile, Heo Yoon-do is a lawyer, but he doesn’t even have an office. He solves small problems of neighborhood residents at a restaurant. He is full of love. Miraculously, Heo Yoon-do is headhunted to join the TOP team at MC Group. The TOP team manages the affairs of the family who runs the MC Group. Their job includes covering up immoral or illegal behaviors done by the family.
Stuntman Cha Dal-geon gets involved in a tragic airplane crash and ends up discovering a national corruption scandal in the process. Go Hae-ri, the oldest daughter of a deceased marine, decides to work for the National Intelligence Service as a secret ops agent in order to support her mom and younger siblings, although all she wanted to do is to become a civil servant.
Justice menceritakan tentang kisah seorang pengacara, Lee Tae Kyung (Choi Jin HyukO) yang membuat kesepakatan dengan iblis untuk membalas dendam. Sementara, Song Woo Yong (Son Hyun Joo), merupakan seorang pria yang rela menjadi jahat demi keluarganya
Kedua pria ini memiliki kemiripan, yakni sama-sama membuat kesepakatan dengan iblis untuk mengabulkan keinginan mereka. Lee Tae Kyung mengumpulkan kekuatan dan kekayaan dengan berurusan bersama klien-klien kelas atas. Kasus yang ia dapat biasanya berasal dari Song Woo Yong yang merupakan pemilik perusahaan konstruksi.
Terdapat serangkaian kasus, di mana beberapa aktris dilaporkan telah menghilang dan membawa Lee Tae Kyung dan Song Woo Yong bekerja sama dan terlibat dengan kehidupan serta rahasia dari orang-orang kalangan atas. Hubungan mereka berakhir saat mereka harus saling mengandalkan satu sama lain.
An explosion at the National Assembly kills everyone in the cabinet, leaving Park Mu-jin, the Minister of Environment, to become the next president. Park Mu-jin is a scientist-turned-politician who has no ambitions in politics, but as the acting president for 60 days, he is compelled to investigate the truth behind the attack. Based on the popular American series Designated Survivor.