Helaman covers the generation after Alma's ministry, narrated first through the record of Helaman, son of Alma, and then his sons Nephi and Lehi. Nephi eventually gives up the judgment seat entirely to preach full time, a choice the text frames as a rejection of political power in favor of prophetic calling, and much of the book follows his and his brother Lehi's ministry, including a notable episode of imprisonment among the Lamanites in which the text describes them being encircled by fire without harm, an experience credited with prompting a Lamanite conversion.
The book's best known episode belongs to a different figure: Samuel, a Lamanite prophet who preaches to the Nephites in Zarahemla from atop their city wall after being refused entry, prophesying signs that will accompany the birth of Christ, a night without darkness and a new star, and later signs that will accompany his death. Samuel's sermon is delivered from outside the community he addresses, a detail later commentary has read as significant given that a Lamanite, from the people generally cast as the Nephites' rivals, delivers one of the book's central prophecies.
Samuel's prophecy of a night and a day and a night together with no darkness, and of a new star appearing in the sky, gives Helaman its clearest forward link to 3 Nephi, where the text presents those very signs as fulfilled at the moment of Christ's birth on the other side of the world.