Limhi rejoices upon learning Zarahemla has not been destroyed

Perhaps you've read the Book of Mosiah at least one time in your life.  Do you recall King Limhi?

When Ammon (the explorer from Zarahemla) first meets the king, the king rejoices to learn that his brethren in the land of Zarahemla are still alive.

Now, I know of a surety that my brethren who were in the land of Zarahemla are yet alive. And now, I will rejoice; and on the morrow I will cause that my people shall rejoice also.

This begs the question...

Why did Limhi believe they were dead?

This question is not immediately answered, but 14 chapters later, we get a more detailed account of the struggles of Limhi. In that account, found in Mosiah 21, we get the answer to our question (an answer which brings up an entirely different mystery):

25 Now king Limhi had sent, previous to the coming of Ammon, a small number of men to search for the land of Zarahemla; but they could not find it, and they were lost in the wilderness.
26 Nevertheless, they did find a land which had been peopled; yea, a land which was covered with dry bones; yea, a land which had been peopled and which had been destroyed; and they, having supposed it to be the land of Zarahemla, returned to the land of Nephi, having arrived in the borders of the land not many days before the coming of Ammon.

The Book of Mosiah is complicated!