Outlier Earth

Our central worldline monitors many of the adjacent worldlines. Are we behind or ahead of other worldlines technologically? Could people cross over and be a threat? Do they have any technology we could use to stay dominant?Of all the alternate Earth timelines, only this one had the North American natives survive and flourish. This, despite enduring a vastly superior Alien invasion centuries previously. Two agents sent from the central worldline to investigate this outlier Earth have disappeared. An agent sent by the Central Worldline, despite his apparent youth, and disregard for protocol, is sent to investigate the Outlier Earth for an explanation.