Throughout his life, Uatu followed a moral code based on passive observation of the events of the Earth. Now, when he was murdered at the beginning of Original Sin, all the secrets that he was the guardian of are revealed. Iron Man and Hulk discover as well as an episode of their past binds their destinies, while Thor and Loki learn that Odin has hidden the existence of a Tenth Kingdom. What decisions will these four heroes make following these revelations?