Ji Seung Yeon fails her audition piece for an English music college by severely modernizing it, secretly returning home to South Korea in shame. Hiding out at her painfully shy friend's house, she joins him in auditioning to replace popular members of a boy band who are getting too old. Together, she and her friend make it through to a finalized group of eight competing for the few opening spots. No one but her friend and her uncle (director of the pop music company) and his assistant know she's a girl. The leader of the boy band, not in the know, starts questioning his orientation when finding himself progressively attracted to this "boy."
Failing her British college entry exam, Ji Seung Yeon returns to South Korea where she has several unfortunate run-ins with ill-tempered M2 boy band leader Kang Woo Hyun.
A new problem arrives in Ji Seung Yeon's bid for stardom when her uncle, CEO Jang Hyun Suk, recognizes her among the surviving boy auditionees.
Ji Seung Yeon agrees to be Kang Woo Hyun's slave, which will naturally conflict with demands upon her time as an auditionee.
A misunderstanding over a signing event leads the M2 Juniors to pool their talents in order to create a sizable fan base and solidify their position in the company.
The M2 Juniors have one day to gain written approval from individually assigned mentors before Hyun Suk will allow them to perform in a showcase.
All eight M2 Junior members must either put together an acceptable, unanimously-approved performance for a showcase or else accept the event's cancellation.
The Juniors are split into two teams of four for a performance at week's end, but someone makes trouble for Ji Seung Yeon.
The boys perform without Seung Yeon, unaware he's (she's) been locked in her room by her parents for disobedience.
One member of the Juniors asks the group for help while another betrays it. Oh In-Young starts getting fed up with Woo Hyun not succumbing to her charms.
While the M2 Juniors come to terms with Seung Yeon's gender revelation, sabotage lies in wait at their next stage show.
Violence breaks out within M2 when it's believed Woo Hyun planned to jettison his bandmates all along.
Leader Han's immediate plans for Sunny Entertainment don't jibe with Woo Hyun, and photographic evidence later becomes impossible to ignore.
Thanks to Han's planning, fan rejection turns into fan adoration for Woo Hyun and In-young, Korea's new hottest love-couple - which Woo Hyun can hardly abide.
For their final test, the Juniors must pick a rival to compete against. Meanwhile, Seung Yeon's secret finally goes public.