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.

Song Ha-yoon, Lee Jun-young, Yoon Bo-mi, Gong Min-jeung, Joo Woo-jae, Nam Min-woo, Kim Gi-ri, Lee Si-hoon, Park Han-sol