Seo Jeong-ha, a senior in college, decides to sell a speaker her ex-boyfriend gave her on a secondhand market. Her reason is simple: she has a new crush, the handsome and sweet Park Min-jun, and the speaker has become nothing but a nuisance. However, as she goes to complete the transaction with a sense of relief, the person who shows up to buy it is none other than her ex, Choi Seo-hun. 'How could you sell this for only 180,000 won when it costs so much more?!' A love triangle romance drama sparked by a secondhand trade!