Set up. A nerve agent that kills in minutes. Vx, the nerve agent, is one of the most dangerous substances out there. Was the kid brother who President Trump calls little rocket man responsible . You knew this was kim jonguns order. Only one person who can make that order and thats kim jongun. Tonight, eyeopening access to a story most americans have never heard. Just waving out to the crowd. Our 20 20 investigation with bob woodruff, one of the few journalists ever to visit the hermit kingdom. Three continents in three months. What were seeing is, there he is walking in to the airport. Those still in danger. My father has been killed a few days ago. Those who fear for the families that this game of thrones could kill. The entire family, theyre all gathered up and all killed. A dynasty, a murder, and a shadowy kingdom. Im david muir. Im elizabeth vargas. And this is 20 20. You could not have had a crazier story. It was like a movie, it really was. It was planned. It was executed in a pr