It will be recalled that after the Nephites and Mulekites became one people, a group of Nephites became isolated in the land of Nephi and were virtual slaves of the Lamanites. The king of these people was called Limhi, and he sent 43 men northward to locate the main body of the Nephites, thinking they might rescue these Nephites who were in slavery. However, these 43 men became lost and after completely missing the land of Zarahemla, they wandered up into the land northward. To their amazement, they found the entire country covered with bones and the ruins of cities. They thought these ruins must have been the remains of the Nephite civilization, when they were actually the ruins of the Jaredites who had become extinct through civil war.
However as the search party proceeded further north they discovered a set of 24 gold plates, which were filled with writings they could not read. Finally the search party gave up and returned home the same way they had come, so once again they missed the land of Zarahemla. Nevertheless, they brought with them the 24 gold plates, which were later translated by the Urim and Thummim. These plates contained the history of the Jaredites written by Ether, their last prophet, and that is what we are now reading.