In "Scholar Walking in the Night" Lee Joon Ki used Lee Yoo Bi's life as collateral. With that, he negotiated with Jung Kyu Su.

On the 9th episode of MBC Wednesday/Thursday drama "Scholar Walking in the Night" broadcast on August 5th, Kim Sung Yeol (played by Lee Joon Ki) made a proposal to suggest something to Jo Saeng (played by Jung Kyu Soo).

On this day, Kim Sung Yeol asked, "Did you see me ten years ago at the house of Suh Jung Do?" Jo Saeng said, "I watched with my two eyes. That you killed a person and you ate this person and killed them." With that, he started to shake.

Kim Sung Yeol said, "I'm also a vampire like this person so it's natural that you're in fear. For 120 years, I've tried to get rid of this person and have been looking for this secret record. To keep the king's heirs, he made Yang Sun into a vulgar man. He said that he would not leave them alone" and convinced him.

In particular, Kim Sung Yeol said, "If you let me know where this record went, then I will let you survive. Yang Sun and your remaining dependents will be able to live.