In the episode of the SBS drama 'To the Beautiful You' that was aired on the 5th of September, a song battle was seen between Goo Jae Hee (played by Sulli) and Seol Han Na (played by Kim Ji Won).
Seol Han Na attends the after party along with the Genie High School boys. They are enjoying themselves at a karaoke when Seol Han Na says that she wants to sing a song. The song that she choses is IU's 'Nagging.'
Seo Han Na sings the song with a pretty dress on and while making cute facial expressions. Then she hands a mike to Kang Tae Joon (played by Min Ho) and asks him to sing the next song with her. The friends cheer them on and seeing this, Goo Jae Hee becomes sullen and leaves.
Goo Jae Hee then goes to the dog Sang Choo and tells him that she could also sing that song. She then pretends to hold a mike and starts to sing IU's 'Nagging' in front of the dog. The song battle between Sulli and Kim Ji Won is attracting much attention.
On the other hand, in this episode, Seol Han Na becomes suspicious of Goo Jae Hee and starts to look into her background information.