Summary:  Seung gi a playboy meets yoona a quiet shy girl who works at the library, He made a bet with his friends that he would sleep with her,so he disguise himself as a weak nerdy boy. and end up sleeping with her,years later yoona finds out her babies father is actually a millionair. How will yoona deal with this secret? and what will happen when he's mother finds out.

Minjae seven year old

 twin sister minsuh