A long time ago in a galaxy far far away... granted the Book of Mormon might have been more exciting if it had light sabers and wookies, but what are you gonna do, it was written in the 1830's.
Here's the plot break down really quickly.
A family from the tribe of Manasseh, was told by God to get the hell out of Jerusalem. They peaced out, built a boat and with the Lord in their sales went to the 'promised land' (America). No one knows where in America (my Dad, who spent his summers in Guatemala and Mexico studying this, says Central America) but everyone has a theory.
The family had many members, but the key members were a good son and a bad son. Nephi = good, Laman = bad. The two brother's squabbling sets the tone for the whole book. In fact, there were multiple times when Laman would have killed Nephi, however since Nephi was righteous the Lord saved his ass. That is what is called foreshadowing. (Spoiler Alert!) The book ends with the destruction of the Nephites because they had stopped being righteous, and as a result the Lamanites wipe them out. The Nephites and the Lamanites are always fighting, but sometimes the Nephites are good and sometimes the Lamanites are good, but it's usually the Nephites that are righteous.
During the first 600 years of this story, these people obey the law of Moses. Then around 32-33 AD the earth sneezes, hick-ups, burps, farts, and queefs all at the same time and the result is 3 days of darkness. (Those who knew the signs knew this meant JC would be comin' to town soon. But most people just freaked out.) On the other side of the planet the Jews had just killed the Christ out of Jesus and he was chillin' in the tomb.
Anyway after Jesus woke up and hungout with his bros and hoes, proving to them that he was bigger than both John Lennon and 2-Pac (get it? that's a joke for 2 reasons), he showed the world that he had learned a new magic trick, and teleported himself to America. Not only that, but he gets a talk-show-host-worthy introduction for his dear old Dad. So, he teaches these lost tribesman basically the same things he taught everyone in the New Testament, except this time no one nails his ass to the wall.
After Jesus has taught them everything he thinks they need to know, he takes off. And the Book of Mormon people do pretty good for awhile. But eventually the pessimistic dicks (this is the tribe I came from) cause everyone to be total heathens and both the Nephites and the Lamanites decide to settle their differences in a way that makes the battles in Braveheart, Lord of the Rings, and Saving Private Ryan all look like a toddler playing with his tub toys.
During this time of epic carnage that would eventually kill off every last Nephite, there were two Nephites that still believed in the Gospel of JC. One guy who was basically one of those dudes who runs a rare book story. He was a collector and a reader. He had the writings and scriptures of their people from the time they left Jerusalem, 1000 years worth of writings. This is none other than.... wait for it... Mormon. So have you figured it out yet? The reason the Book of Mormon runs in chronological order is because this dude Mormon made an abridged record of the history and teachings of his people. Unfortunately Mormon died before it was totally complete, so his son Moroni (the gold dude on the top of Mormon temples) finished it. He then grabs a few knick-knacks and his daddy's book and makes a time capsule. He writes one last note in the back of the book and then buries it away where it sat until the Angel Moroni (this is the same guy, just dead now) tried to earn his wings by telling the young Joey Smith about it.
And there it is. That's what's in the Book of Mormon. Here are some cartoons so you can learn more about the book of Mormon without actually having to read it.
http://www.youtube.com/watch?v=BKGEeRBy8ek (Abinadi and the evil Kind Noah (yes, in the Book of Mormon Noah is a bad guy's name))
http://www.youtube.com/watch?v=yKyLYIpZbEY&feature=relmfu (We are as the armies of Helaman, we have been taught in our youth!)
http://www.youtube.com/watch?v=6O5VN_o6tP8&feature=relmfu (And this one is about Mormon and Moroni)
Now, here's my 2 cents.
-Criticisms of the BoM are many. But stop the Archaeological evidence angle as proof that it isn't real. The Book of Mormon people could have been Mayan. It is said that Joseph Smith translated the BoM from reformed Egyptian. Guess who has a whole fucking lot in common with the Egyptians? The god damn Mayans!!!
Stop the DNA angle. People say that Native American DNA and Jewish DNA should be the same since the Native Americans are supposed to be the ancestors of the Lamanites. And Laman was on the boat that came from Jerusalem. Manasseh damn it! People if you don't know what you're talking about shut the hell up! Here's an Old Testament lesson numb skulls: Judah and Manasseh formed 2 different tribes. Guess which tribe the Jews came from? You people want science to help you understand religion? That is easily the most idiotic concept I have ever heard. I'm still waiting for the paternity test the proves Jesus was the son of God!
-Who cares if Joseph Smith made it all up, or if God bestowed magical translation powers on him. Think about the 2 options.
#1 It's true. The whole thing, Mormons, polygamy, becoming a god, they are right and you are wrong.
#2 He made it up! Dude this story is more complex than Harry Potter and Joe didn't take 10+ years to write it all. The dude convinced his dad that he was a prophet! I have never, not once, convinced my dad of anything! He also convinces dozens of woman to marry him. He convinces thousands (during his life) and now millions of people that God restored the truth on Earth through him. He had the balls to say,"Y'all, every single one of you, are wrong! and guess what, I'm right!" Joseph Smith is the most under-appreciated figure in American history.