The next few books - Enos, Jarom, Omni, and Words of Mormon- are each only a chapter long, and most of them are only a brief explanation of the history of the Nephites, as told by whatever record-keeper had the plates at the time. Through the books it is explained that at some point in their history, the Nephites actually became more wicked than the Lamanites. There was a small group of righteous Nephites who were warned to flee, led by a man named Mosiah. The rest were destroyed by the Lamanites, and their lands were occupied.
Mosiah's people, in fleeing the Lamanites, came across a group of people led by a man named Zarahemla. Their language was completely different, but eventually Mosiah was able to teach them the Nephite language, and he discovered they were descended from King Zedekiah, whose son Mulek had been smuggled out of Israel before he could be killed by the Babylonians. He and his followers had crossed the sea as well, but without scriptures, so they had forgotten God. Mosiah's people were able to teach them, and Mosiah was elected the king of the two people. Zarahemla also mentioned that when Mulek's people had arrived, they had discovered a man named Coriantumr, who claimed to be the last surviving member of a powerful nation called the Jaredites (that'll be important later). He lived with them nine months and then died.
By the reign of Mosiah's son, King Benjamin, there was a group of Nephites who wanted to go back and repossess the land of Nephi (the land the Lamanites were currently occupying). A first group started out, but ended up destroying each other, thanks to the fact that half of them wanted to destroy the Lamanites and half of them wanted to negotiate. Those who survived came back in defeat, but eventually a second group, led by a man named Zerrif, set out. They were not heard from again in the lifetimes of their loved ones.
The man who was keeping the record by the end of Omni, named Amaleki, had no family left to leave the records with (his brother had left with Zerrif), and his record ends when he decides to give the records to King Benjamin to care for.
Wow, that was a lot of history in not a lot of time. Huh.
Fare thee well, friend!
P.S. Finals are over! I can start breathing again!