Seo, who was visiting Korea, found a job as a photographer to help promote a new girl group know to be as Gfriend. Recognizing one of the members as her closest friend back in her childhood, Seo soon had gotten to know everyone from the group on a personal level. It was unfortunate that Seo had to return to America for her job, but after a year's worth, Seo managed to come back to Korea along with a surprise in stored for the six members.

Taken by her father's bodyguards, Jei is forced to exist as the identity of her twin brother, Jay. Her father's threat to endanger her mother lead Jei no choice but to comply to her father's wishes, dressing as a man to represent the figure of her brother. Her father wanting to maintain business relations with other companies, Jei has no choice but to also maintain relations with the other companies' daughters, while in the same time maintain her true identity a secret.

A weird phenomenon is occurring to Yuli: swapping bodies with Twice members! Not knowing the cause of this phenomenon, she tries to solve the problem, by meeting the Twice members herself.