I must warn you, from here on down are some spoilers, so if you haven't seen the movie or read the story and want to with a clean slate, stop now...but be sure to come back later! If you have read/watched it or don't really plan to, read on.
On the surface it's a gory story -- the movie begins with a bunch of young adults/kids killing the older townsfolk. They take out all of the adults so they are the only ones that are left. This act is done after one of the kids, their leader named Isaac (Biblical names abound in this story), says that it's "His will." The movie portrays a city of children that believe they are following the will of "He who lives behind the rows," or basically, God, portrayed as a "Beast" or creature of some sort that lives in the corn field. As the movie progresses, you can clearly see that the image of God the children have is very warped.
Here are the bare bones: The story takes place in Gatlin, a small country town in Nebraska. We follow Burt and Vicky, going on a trip to California when they drive through this rural area. The drama begins when Burt hits a boy with his car who's standing in the road. He later finds out though, that the boy was already dead (throat cut) before he hit him -- Burt finds that to be strange. (I'll leave the WHY out here to not spoil everything.) Burt tries to take the boy to the nearest city, which happens to be Gatlin. Upon arrival the town seems deserted. However, as he and Vicky explore, they find there's something very wrong with this place.
Corn is everywhere. It's in buildings, on the walls, coming out of the ceilings, everywhere. The book and movie are slightly different in their portrayal of the journey through the city, but to try and give you the general idea I feel it's better to follow Burt's trip in a church. He finds corn everywhere, a picture of Jesus hangs on the wall but Jesus has a green face and his hair is corn. Then he finds a Bible that has been altered, with stuff crossed out, words added...its been CHANGED.
These kids are following Isaac who they feel is a prophet. They follow him through everything, led like sheep as they kill the parents and try to kill Burt and Vicky. They are serving a "Beast" that lives in the corn field, they believe it to be the true God of the Bible. The corn I believe was used because the town was in a drought and the promise of a good harvest (temptation, used in the metaphorical sense here by King) leads them astray.
Now obviously their view is warped and upon first glance of this (there are many more disturbing images I could portray but I'll leave it at this), it could seen almost anti-Christian. But with many things, you need to check what it's saying before you judge the book by its cover.
What I've taken from this is an extreme example of what happens when we twist the Scriptures to our own ends. When we start taking passages out of context, try to conform Jesus to us instead of us to him, we are not serving God but the "Beast," or more specifically, the Devil. The Bible was altered to follow this false preacher -- literally as verses were changed. But the people were led astray by what they believed was truth, in reality it was not.
Burt makes it clear to them toward the end of how religion without love is not true. He shows them what they are doing, and that it's wrong. He asks what God would want children to kill their parents? The Devil is in Hell, and he wants us there with him and he'll trick us any way he can, including through false prophets and many forms of temptation. It shows, though, how easily people can be led astray, like sheep. It also shows that people can stand strong and that those that remain "righteous" will overcome.
In the end the "Beast" is overcome with a clue in a Bible verse and with fire...just like the real Devil. (Once again I'm going to leave some stuff out so as to not spoil the whole thing.) He's burning in Hell and is overcome by the power of the Word.
People say Stephen King (who is a Christian) is all about thrills, his books aren't always really for Christian readers, etc. But here there is a true Christian message of LOVE, as well as a lesson that we shouldn't bend the Scriptures to fit our own agenda, to our own ends, but rather conform ourselves to Jesus Christ. If we try and form the Bible to us, we are serving the Devil and are destroying ourselves. If you look at the moral underneath the thriller, the blood and gore, you'll find a good lesson that we all should remember. King tells it in a way that won't be easily forgotten, either. And that I think also has its place and is a good point. If the lesson sticks with us, all the better, right?
I would recommend the book and the movie to Christians...with a warning: It is very graphic, it is very strange, but if you keep in mind the message of what King is saying about society, it becomes something great, something special. Granted I think it could have been shown with a little less blood than was in the movie, but that's just directing -- I'll always recommend a book over a movie so if that bothers you, just read the book (it's a short story that probably won't take you more than an hour). There are many more little elements that are in this movie that I could expound upon, but this is already a pretty long post so I'm going to end it here. If anyone wants to get into an in-depth discussion about it with me, send over a comment or message!