In "Who are You: School 2015" Nam Joo Hyuk suspected Kim So Hyun's identity and mobilized herself.

On the 7th episode of KBS 2TV Monday/Tuesday drama "Who are You: School 2015" (script Kim Min Jung, Yim Ye Jin, director Baek Sang Hoon, Kim Sung Yoon) broadcast on May 18th, Han Yi Ahn (played by Nam Joo Hyuk) found that there was a scar that she did not find on Ko Eun Byul on Ko Eun Byul's body.

On this day, Ko Eun Byul called Han Yi Han and said that she was going to go in front of the gym. Yi Ahn who had been in front of Eun Byul's house ran to the gym and then leisurely came back outside. The two looked at each other and smile as they were playing video games and had a fun time.

As the night got darker, the two people were on a park bench together.

At this time, Ko Eun Byul misstepped and fell down by accident. Yi Ahn was surprised and raised her up after being surprised. At this time, they found a scar on Ko Eun Byul's arm. Lee Ahn said, "I didn't see this scar. When was it formed?"