A talk show that began airing on tvN in June 2017, directed by PD Na Young-seok. A mysterious chat explosion from polymaths across politics-economy X gastronomy X literature X neuroscience. Wherever they go, they travel as their feet take them and pour out whatever comes to mind. Four "ajae" (middle-aged men) experts, as smart as they think they are and more delightful than expected, along with entertainment industry representative intellectual Yoo Hee-yeol, embark on a mysterious chat journey that may not be particularly useful, but is exciting to know.