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On the December 7 episode, the pianist led Lee So Yeon into a concert hall, but when she walked towards the piano, she found that Yoon Han wasn't behind the keys. 

Instead, he stood on stage and said, "So Yeon. I thought a lot about what I should say when I stood here, but now that I'm here, I can't think of anything. Though we haven't gotten to the point where our marriage is real to us, at this moment and place, I want to sing for you." Yoon Han then sat at the piano and sang "Marry Me", which he composed himself. 

Yoon Han later got on one knee and proposed to her, kissing her on the forehead afterwards. Lee So Yeon shared, "I don't really remember. It felt like I was floating on air. I was so happy. I wondered how I could be so happy."