Most good stories start with a fundamental list of ingredients: the initial situation, conflict, complication, climax, suspense, denouement, and conclusion. Great writers sometimes shake up the recipe and add some spice.
Exposition
Meet Me at the Fishin' Hole
We begin in Maycomb, a sleepy little town in Alabama. The good: our heroes, the Finches, have lived there for generations and feel right at home in their friendly, cozy community. The bad: this friendly, cozy community isn't so friendly and cozy with the blacks. This is 1930s America, and racism is the name of the ugly game. Our unnamed narrator gives us all the deets we need to understand the conflict that's about to erupt between the anti-racist Atticus and his racist but beloved neighbors.
Conflict
All Men Are Created Equal...
… except for black ones. And (wo)men. Super dad (and lawyer) Atticus agrees to defend a black man, Tom Robinson, on charges of raping a white woman, even though public opinion is against him in a major way.
The battle between Atticus's desire to give Tom the best defense possible and other people's desire to preserve the status quo fuels a lot of smaller conflicts between our heroine Scout and her peers.
Complication
The Status is Not Quo
At the trial, it's obvious that Atticus is right and his opposition is wrong … but that doesn't mean much in a time and place where the color of your skin means a lot more than the cut of your jib. Or the truth of your words.
Climax
We Find the Defendant Delightful!
And the status quo wins. Despite Atticus's best efforts, and Jem's belief that the people of Maycomb couldn't do something so fundamentally wrong as send an innocent man to the electric chair, the jury convicts Tom. Game over. Or at least, game changer.
Suspense
Game Not So Over
It turns out that Mr. Ewell just won't stop playing. He threatens Atticus, harasses Helen Robinson (Tom's wife), and is generally a really ugly person. Jem and Scout are super worried that he's going to hurt Atticus.
Denouement
Hamburgler
Mr. Ewell finally strikes, ending the suspense, but Atticus isn't his victim. Instead, he targets Jem and Scout—and gets killed in the process. Oops.
Conclusion
Boo!
This could almost be another climax, since the book has been talking about mysterious shut-in Boo Radley from the first page, and now he finally appears as the hero who saves Jem and Scout from Mr. Ewell. But instead, it's a moment for Scout to grow up: she finally leaves behind the fantasies in order to see Boo as a real person.