Seul Gi gets a new job at a chocolate company and works hard, but can't seem to adjust to its atmosphere. She tries to overcome her alienation with her positivity, but constantly gets hurt. One day at Honggeumdang, a place she visited to fix her broken watch, she falls in love with the charm of handmade chocolate. She soon becomes the only member of a task force for an in-house contest for Valentine's Day and collaborates with the owner of Honggeumdang to create the best chocolate ever. However, it isn't easy to find teammates. Just then, Hyun Nam, the chocolate maniac, and Jeremy, the extrovert social media influencer, appear. Will the unique trio and the strangely cool Mr. Hong be able to create the ultimate chocolate that will charm everyone on Valentine's Day?