Seo Ji-kang, played by An Woo-yeon, is an essay writer who voluntarily becomes a couple tour guide to observe lovers closely. He is a person who distinguishes exactly what to do and what not to do and moves according to his plan, but becomes increasingly fond of Ha Song-i ( Bang Minah) who unexpectedly jumps into his life. With Ha Song-i between them, he and Park Do-gyeom ( Kwon Hwa-woon), her ex-boyfriend, create a love triangle. In addition, meeting