The book begins in Jerusalem at the time of King Zedekiah, where Nephi's father, Lehi, has a vision, wherein he sees God the Father, Christ, and the twelve apostles. Lehi is also made aware of the imminent Babylonian destruction of Jerusalem. Hence as a result of this experience, Lehi begins to preach repentance to his people. As with the other prophets living at that time, such as Jeremiah, they reject his teachings and attempt to kill him by stoning him.
In a dream, God commands Lehi to leave Jerusalem with his family (which include his wife, Sariah, and his four sons Laman, Lemuel, Sam, and Nephi). Yet almost immediately upon their exile, Lehi is commanded by God to send his sons back to Jerusalem to retrieve the brass plates, a record similar to the Old Testament which was owned by Laban, a powerful leader in Jerusalem. Nephi returns with his brothers and after several failed attempts, where Laban even tries to steal Lehi's property and murder his sons, become frustrated. Laman and Lemuel take out their frustration by beating Nephi. An angel appears and commands Laman and Lemuel to stop beating Nephi and return to retrieve the plates. Nephi returns alone, finds Laban passed out from drunkenness, and kills him with his own sword as directed by the Spirit of God. He then disguises himself as Laban and fools Zoram, a servant of Laban, into taking the plates outside the city to his brothers. Zoram, discovering Nephi's trick, goes to flee, but is persuaded by Nephi to travel with Lehi and his family and they return together with the plates.
After receiving the brass plates, Lehi spends time studying them. He discovers it contains a genealogy of himself, and that he is a descendant of Joseph, the son of Jacob. It also the contains the five books of Moses.
Lehi's sons return to Jerusalem a second time, as directed by the Lord through the prophet Lehi, to retrieve the family of Ishmael. Meeting Ishmael, they convince him and his family to leave Jerusalem together with Lehi's family. On the journey back to camp, Laman and Lemuel and some members of Ishmael's family rebel. They want to return back to Jerusalem. After a stern lecture by Nephi, where he reminds them of the prophecies and offers them a choice, they tie him up and leave him to die in the desert. However, Nephi is able to escape from the ropes. Upon finding the group, Laman and Lemuel try again to hurt Nephi, but they are softened by the daughters of Ishmael and ask for forgiveness from Nephi.
Returning again to camp, Lehi has a dream where he sees The Vision of the Tree of Life, with fruit that is "desirable to make one happy." Relating this vision to his children, he expounds on it by teaching about the Redeemer and the need to follow his counsel by keeping the commandments. Nephi desires to receive a similar vision, and asks the Lord for the vision and its interpretation. Nephi is swept away by the spirit and sees the vision his father had described. He is also given an explanation about its symbolism: the tree and its fruit represent the love of God, a "rod of iron" represents the word of God, and a "great and spacious building" represents the pride and mocking attitude of the world. Nephi is shown many past and future events, including the birth, ministry, and death of Jesus Christ. He also sees Christopher Columbus traveling across the Atlantic ocean, the American Revolutionary war, and the scattering of the "seed of my brethren." Other events include the coming forth of the Book of Mormon, it being a record made by the ancestors of the Indians, and also what is believed to be the founding of The Church of Jesus Christ of Latter-day Saints, although it is not mentioned by name, yet there are described several events which imply movements and church formation. Future events are also taken into account, such as the coming forth of scripture even after the Book of Mormon, that would make truths known which were taken out from the New Testament, a concept discussed in the several passages of this vision. Nephi begins to see wars and rumors of wars taking place in the future, and also other events. However, he is forbidden to write about such things because John the Apostle is to write about them in the Bible. Most importantly, Nephi sees the future of his generations and the generations of Laman and Lemuel. Whereas his people will have the gospel and will ultimately be destroyed for wickedness, the children of Laman and Lemuel will be raised without a knowledge of the gospel, survive the generations, and be taught by the Book of Mormon and the future church.
After Nephi's vision, he sees Laman and Lemuel, who are arguing over the meaning of Lehi's vision. Nephi chastises them for not asking the Lord for the interpretation, and explains the point they were disputing. He pleads with them to soften their hearts and submit themselves to the Lord.
After the sons of Lehi marry the daughters of Ishmael, a "a ball of curious workmanship" is discovered at Lehi's tent door. Using the directions on the ball, they begin journeying eastward along the Red Sea. As they travel along the banks of the Red Sea, Nephi's steel bow breaks while hunting. Upon hearing the news, the entire camp begins to complain and speak against the Lord for their misfortune, including Lehi. Nephi builds a new bow and arrows out of wood, and then enquires of Lehi where to hunt. Humbled, Lehi repents and turns to the Lord, and Nephi is able to find food for the camp. Looking on the ball, they discover a message that caused them to "fear and tremble exceedingly". The ball works by their faith. As long as they are faithful, it will lead them through the most fertile parts of the land. If they are not, it will not function properly and they will be left to their own devices.
Ishmael dies on their journey near a place called "Nahom". This is one of the few places listed in the Book of Mormon that relates to the Old World. In mourning, Ishmael's daughters complain against Lehi and Nephi, and desire to return to Jerusalem. Laman and Lemuel decide to kill Lehi and Nephi, but voice of the Lord speaks many words to them and chastises them severely, causing them to change their minds and repent.
Arriving in a place they call Bountiful, on the borders of the sea, they set up a camp. After many days, the voice of the Lord comes to Nephi and commands him to go up the mountain. Once on the mountain, the Lord instructs Nephi to build a ship, and describes how to build a ship and how to make the tools needed. Nephi returns to camp and begins working to build the ship. Laman and Lemuel see Nephi and mock him for trying to achieve an impossible task. Nephi lectures them about the strength of the Lord and how impossible things are possible when the Lord commands it. Being filled with the Spirit, he commands Laman and Lemuel not to touch him or they would die instantly. He also commands them to assist in building the ship. Laman and Lemuel repent again, and begin helping Nephi build the ship. The Lord commands Nephi to touch them, saying it will not kill them. He touches them, causing a shock, and they do not die. Laman and Lemuel proclaim to Nephi, "We know of a surety that the Lord is with thee".
After completing the ship, the voice of the Lord goes to Lehi and commands him to load his family and supplies on the ship. They depart on the ocean. Many days later, Laman and Lemuel and the sons of Ishmael begin partying, dancing, singing, and being rude. Nephi, fearing that the Lord would be angry with them, speaks to them. They get upset with Nephi and tie him up. The compass—the ball of curious workmanship—ceases to function, and they get caught in a terrible storm. At the pleading of their wives, and for fear of sinking, Laman and Lemuel release Nephi. Nephi prays, and the storm stops, leaving a great calm. Many days later, they arrive in the promised land, on the American continent.
Upon arriving in America, they begin building farms and raising livestock that they find native to the land. Nephi is commanded by the Lord to make the small and large plates of Nephi. On the small plates, he is to write the spiritual record of the people, and the more plain and precious parts. On the large plates, he writes the history of the people, including their genealogy.
The last parts of First Nephi contain some teachings from Nephi to his people concerning Jesus Christ. He quotes Isaiah chapters 48 and 49 from the Old Testament. He ends the first book showing how all the ancient prophets have testified of Christ, and how it is only through Christ that one can be redeemed from the fall of Adam and their sins.
First Nephi contains many vital doctrines to Mormonism in general.
Nephi states many times while making the record that he intends to show the mercy of the Lord and convince the readers of the necessity and divinity of Jesus Christ. He shows how Laman and Lemuel, though they rebel many times, repent and are frankly forgiven by the Lord. He shows how the Lord is willing to answer prayers, protect those who trust him, and guide those who are willing to obey. He begins with this message; and he ends with it as well.
Included is a model of how prophets are called and how they operate. For instance, both Lehi and Nephi received their callings by revelation and visions from the Lord. This is not much different from how Joseph Smith, Jr. received his calling. Nephi also expounds on the doctrine that all prophets teach of Christ by quoting Isaiah and other prophets.
Nephi also teaches that through faith, the impossible can be done. "I will go and do the things which the Lord hath commanded, for I know that the Lord giveth no commandment unto the children of men, save he shall prepare a way for them that they may accomplish the thing which he commandeth them."  He teaches that God is all-powerful, and that man can do all things that the Lord desires them to do.
Many prophecies are made that are fulfilled within the pages of the Book of Mormon. The most important prophecy concerns the destruction of the Nephite people, which occurred, according to the Book of Mormon, about AD 400.
There are several prophecies that are made that can only be fulfilled outside of the Book of Mormon. Key among these are the prophecies concerning the birth, life, and death of the Savior. Nephi records that Jesus would be born to a virgin, conceived by the Spirit; that Jesus would be baptized; that there would be twelve disciples; that he would heal the sick and bedeviled; that he would be judged by the world; and that he would be crucified.
In First Nephi, Nephi tells of his father Lehi prophesying that Jerusalem would be destroyed by the Babylonians.
Nephi also prophesies concerning the future of the American continent. He sees people flee from Europe to settle in America; that the Bible (a record from the Jews) would travel among the people; that the people settling in America would drive the indigenous people out of the land; that the settlers would overpower Europe; the discovery and translation of the Book of Mormon; and that the apostle John the Revelator would write concerning the final days.
- 1 Nephi 8:10
- 1 Nephi 11
- 1 Nephi 13:12
- 1 Ne. 13:17-19
- 1 Nephi 13:14
- 1 Nephi 13:34-36
- 1 Nephi 13:35-37, 42
- 1 Nephi 13:39
- 1 Nephi 13:20-27, 40
- 1 Nephi 18:21