Choco Bank is a romantic comedy about a young man named Kim Eun Haeng who is struggling to find a job after graduating from college. He meets a mysterious woman named Ha Cho Co who offers him a job at her chocolate store. As Eun Haeng learns the ropes of the business, he also begins to develop feelings for Ha Cho Co. However, he soon discovers that she has a secret past that may threaten their budding relationship.