"You're the Best Lee Soon Shin" Yun Da Hun investigates IU's background to figure out who she is.

April 28, the 16th episode of the KBS weekend drama "You're the Best Lee Soon Shin" featured Hwang Il Do (Yun Da Hun) getting suspicious of Lee Soon Shin's (IU) identity. He begins to suspect that Lee Soon Shin may be Song Mi Ryung's (Lee Mi Sook) daughter.

When Hwang Il Do meets a reporter who had previously caught on to his mistake in wording, he hesitates. Reporter Park says, "Is it true that Song Mi Ryung has a daughter. Didn't you say that she's pretending to have been single all her life when she gave birth when she was young?"

Hwang Il Do hesitates and says, "I must be crazy. It's not true." However, the reporter says, "That daughter, does they keep in touch? How old is she now? Does she know how well her mother is doing?"

Hwang Il Do replies, "I told you it's not trie" but the reporters smiles and says, "Scared already. I'll contact you when the truth comes out so that you can confirm on the details."

Realizing there will be way to avoid this, Hwang Il Do begins to collect his thoughts, "What year was that" and begins to remember Lee Soon Shin.

Hwang Il Do looks at Lee Soon Shin's birthday and says, "Can't be" and begins to investigate.