College student Da Eun (Seo Ji Soo) works at a cafe alongside her friend and cafe owner Ji Han (Park Geon Il). One day, Ji Han’s little sister remarks that Da Eun bears a striking resemblance to idol star Byul (also played by Seo Ji Soo). When Da Eun happens to deliver food to Byul’s entertainment company, the person who answers the door agrees, prompting him to ask if Da Eun could serve as a body double for Byul, who’s currently struggling with depression. Da Eun agrees, and the two girls swap lives for seven days. Coincidentally, both girls happen to fall for the boys they’re spending time with: Byul develops feelings for Ji Han, while Da Eun grows close to male idol Jung Woo (Shin Jun Seop)... but they don’t know that Da Eun and Byul have swapped identities! How will Da Eun and Byul handle their new lives?