Eun-soo and Eun-ha, a couple, run out from a successful music production company to show off their individuality and form the EunHaSoo band with Dong-eun. Meanwhile, Dong-eun, who was investing coins to earn living expenses, touches the band's money and loses it in an instant. Angry, Eun-soo and Eun-ha sell Dong-eun's guitar at a used market, and at that moment, Dong-eun appears with the money. As Eun-ha and Eun-soo encounter the lives of people who have purchased guitars in search of a guitar that means a lot to them, they realize what it means to put their heart into music. What does the guitar mean to Dong-eun, and what journey will the three go on to find it?