After three years of peace and prosperity under King Mosiah, the people began to continually pester the king to send down an expedition into their original country of Lehi-Nephi to determine what happened to them.
It seems strange that King Mosiah would place a man in charge of the expedition named Ammon who was a descendant of Zarahemla. He had never been to Lehi-Nephi and apparently wasn't related to any of the first expedition. But it was inevitable that this would be a desperately difficult journey because no one knew how to maneuver their way through the narrow strip of mountainous wilderness so as to reach their destination.