Seo Ji Sung is a programmer of the AI smart home appliance development team. One day, she accidentally develops an AI program called Cho Sang Shin, which will identify trashy humans, and she uses it to save people who are in difficult relationships. Jung Kook Hee is a firefighter who doesn't use social media. He is the one and only person that Cho Sang Shin is unable to analyze.
The show follows the hectic lives, romantic relationships, and love for food of three siblings, Han San Hae, Han Jin Mi, and Han Jung Shik, supposed modern-day decedents of the legendary Dae Jang Geum.
Young-mi, the bookkeeper at a factory, is ridiculed for her dowdy appearance and called 'Ms. Apocalypse' by her colleagues. Do-young, a delivery driver, is the only one to show her any decency and kindness. As her feelings for him grow, Young-mi strives to get him off the hook even when she finds out that Do-young has been embezzling company money. It becomes the last day of 1999, and in the midst of people's fear that the world will come to an end, Young-mi gets arrested for aiding Do-young's crime. And thus, her new millennium starts wretchedly. As she walks out of prison after a few months, she comes across Do-young's wife, Yu-jin, waiting for her and this unexpected visitor makes an implausible but compelling offer.
