An episode of "Dream High 2" was aired on the 28th of February. This episode showed the students at Gi Rim Performing Arts School auditioning at the Super Idol Auditions. When NaNa (Hyo Rin) appeared on stage, she unexpectedly completely missed a note.

NaNa thought it was just a cold so she didn't even go to the hospital to get her throat treated. She believed that she could perform well on stage even without any treatment. While she was on stage however, she made the biggest mistake in front of all the teachers and students. NaNa, as well as her team members, were shocked since Na Na is known to be a powerful vocalist.

When Na Na went to the hospital, she was diagnosed with a Submucosal Vocal Cyst which meant that she had to get surgery to remove the cyst. However, her voice could change as a result of the surgery. NaNa, shocked from the news, decides to quit school.