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
What, Doesn't Everybody Have an Island?
On the surface, Cadence Sinclair's life appears to be pretty sweet. Not only does she live in a big, fancy house in Vermont, her family also owns an island off the coast of Massachusetts called Beechwood, where she spends every summer. She even has a foxy summer boyfriend named Gat, whose uncle Ed is her aunt Carrie's partner.
Cadence, Gat, and her cousins Johnny and Mirren (a.k.a. the Liars) are all fifteen years old, and "summer fifteen," as she calls it, promises to be another season of fun in the sun, funded by her rich grandfather, Harris. Picnics, beaches, private boats, and five adorable Golden Retrievers with whom to frolic in the sand? Yes, please.
Rising Action
I'm Gonna Need More than an Advil
Something terrible happens during summer fifteen, though—something Cadence can't remember. All she knows is that she woke up on the beach half-dressed and half-underwater, and now she has killer migraines.
She wasn't allowed to go to Beechwood for summer sixteen—instead, she had to spend the summer with her dad (in Europe, but still)—and worst of all, after her accident, Johnny, Mirren, and Gat ignored her emails. Nobody will tell her what happened, and her life now consists of crippling headaches and prescription painkillers. She finally gets to go back to Beechwood for summer seventeen, but only for a month. It's not long, but it's enough time to find out what's up with Gat.
Climax
Paper Towels: Use Only as Directed
When Cadence gets to Beechwood, she learns that Clairmont, her grandparents' massive house, has been replaced with a house everyone calls New Clairmont. Nobody will tell her why—they say Cadence's doctors want her to remember on her own.
Gradually, she starts to remember bits and pieces of summer fifteen. During her last week on the island, it all comes back to her: The Liars committed arson. They were sick of listening to their mothers fight over Harris's will, so they took matters into their own hands and burned Clairmont to the ground, dousing the rooms with gasoline and using flaming paper towel rolls as torches.
Falling Action
Giving New Meaning to the Term "Friendly Ghost"
After she remembers what happened, Cadence goes back to Cuddledown to confront the Liars. They confirm that her memories are correct: Not only did they burn the house down, but Cadence was the only one who escaped. That's right; they're all actually dead. Are they ghosts? Hallucinations? Memories? It's not clear, but it doesn't really matter—the point is that they were finally there for Cadence when she needed them.
Resolution
At Least I've Got a Cute Swimsuit
From Gat's faded t-shirt to Mirren's cheesy tourist-town bikini (seriously, it says The Vineyard is for Lovers on the butt), the Liars have been wearing two-year-old clothes all summer, and now Cadence knows why. They tell her it's getting hard to stick around, so she goes with them to the beach to say goodbye. One by one, they walk into the water and go to wherever it is ghosts go. Cadence thinks of all the things they dreamed of but will never have, and resolves to, as Mirren said, "be a little kinder than you have to."