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.
Initial Situation
We meet most of the major players here as Walter's story—and his life-altering involvement with both Anne and Laura—get set into motion. Walter falls in love with Laura here as well, which becomes a crucial detail for the rest of the story.
Conflict
After Walter high-tails it out of Limmeridge, we get an interlude of rising tension and crises that end with Laura's ill-fated marriage to Sir Percival.
Complication
This section is notable for the fact that it's almost exclusively narrated by someone other than Walter (mainly Marian). Laura's marriage to Sir Percival is one disaster after another. Count Fosco arrives on the scene. And our heroines are in seriously dire straits by the end of this stage.
Climax
After danger, illness, near death, fake death, and a break-out from an asylum, Walter dramatically reunites with his BFF Marian and his lost love Laura.
Suspense
While Laura regains her strength, Walter and Marian work to get her justice. Walter finally learns Sir Percival's secret and then witnesses his terrible death in a fire. Cosmic justice, yo.
Denouement
After Sir Percival's death, Walter turns his attention to Fosco and, with some unexpected help from his friend Pesca, finally confronts Fosco. Fosco writes a letter confessing everything he did to Laura and then flees the country. He turns up dead in Paris not too long after.
Conclusion
Everything wraps up nicely, Walter and Laura have a son, and the young family (along with Marian) inherits Limmeridge after Uncle Fairlie dies.