After marathon runner Suji's twin sister, Korea's top celebrity, passes away in an accident, Suji loses the light in her life; Suji gives up running to work part-time jobs.

Suji goes to Suah's shrine the day after the first anniversary of her death to avoid seeing anyone, only to run into the man who created idol group Red Queen -- Korea's top producer, Shinhyuk Kang; the man offers Suji a suggestion.

The ten girls come to 825 Entertainment, ready to become idols, but Shinhyuk makes an unexpected announcement -- the girls have just one week to prepare for a mock test; they must figure out how to work as a team despite barely knowing each other.

The girls start off the Survival Competition by splitting into two teams; the Debut Team, led by Youngjoo, prepares their song selection and outfits for the first challenge while the Rookie Team struggles to get it together.

The girls face an unexpected dance battle, after which the loser must clean the dance studio; Suji shocks the girls as she feels the rhythm and dances her best; Youngjoo notices that Suji has talent, causing jealousy and tension to sprout.

The day for the girls to show their performances to the world arrives; everyone looks forward to the broadcast, but the comment section only talks about the relationship between Suji and Suah, making the other girls green with envy.