Da-eun, a college student who is still finding her career path, becomes Byul, who has been a singer since she was young. Da-eun spends time with a celebrity named Jung-woo and experiences the dreamy life of luxury, while also seeing its dark side. Byul also experiences the preciousness of everyday life, something she hasn’t felt in a while as she became a clumsy part timer at a café with Ji-han and Ari.

Da-eun works part-time and Kim Byul is an idol. These two girls who look alike decide to change each other's lives just for 7 days. And now 1 year later, they decided to change one more time because of one event! A special one week is about to start anew.