Where the Crawdads Sing follows Kya, a girl who grows up on the remote marshes of North Carolina. The text punctuates Kya's story with scenes of detectives investigating Chase Andrews' murder, for which Kya will stand trial.
At the beginning of the text, six-year-old Kya watches as her mother, then her siblings, leave the marsh to escape their abusive father. Before he leaves, Kya's brother Jodie instructs Kya to "Run deep in the marsh" and "hide in the bushes," covering her tracks as Jodie taught her. This advice serves Kya well throughout her life; Kya learns to avoid her father and provide for herself while evading the local authorities who would put her in foster care. Briefly, Kya and her father bond until a letter from Kya's mother sends him into a rage, and he abandons Kya. With help from a local shop owner, Jumpin', Kya creates a self-sufficient life, learning to cook, make money, and live in union with nature. In town, Kya is known as "the marsh girl," enduring harsh prejudice from locals who think she is "plumb nasty" and "swamp trash."
As Kya grows older, she accepts that her family will never return. She befriends Tate, an older boy who knew Kya's brother, Jodie. Since Kya was humiliated on her first and only day of school, she never learned to read, and Tate offers to teach her. Throughout their reading lessons, Kya and Tate develop a romance. Tate leaves for college and promises to return but doesn't show up at the appointed time, believing Kya "could not fit in the academic world." After Tate's abandonment, Kya retreats further into her isolation, refusing to trust anyone. Kya devotes herself to her survival and documenting the marsh ecosystem with detailed notes and lifelike paintings. The town continues to shun her and spread vicious rumors about her, claiming she is " part wolf or the missing link between ape and man."
In her late teens, Kya meets Chase Andrews, the popular, wealthy former quarterback and town "golden boy." Though Chase and Kya have little in common, they begin a romantic relationship because Kya craves human contact, and Chase wants to be the first to sleep with the fabled "marsh girl." Kya initially rejects Chase's advances, knowing he will likely abandon her. As the years go by, Chase talks about their future as a married couple, making Kya feel secure enough to trust Chase. She gives him presents, including a shell necklace and a journal full of paintings of their time together. Tate returns to apologize to Kya and confess his love for her; Kya reacts by screaming at him and throwing rocks, expressing her hurt and resentment after his abandonment. Tate warns Kya that Chase "goes out with other women" in town and sleeps with Kya in the marsh. Tate also encourages Kya to submit her research to a publisher.
Kya publishes her writings and paintings and uses her earnings to purchase her family's land and renovate her shack. Kya discovers from a newspaper announcement that Chase is engaged to his childhood friend, Pearl Stone, and ends her relationship with Chase. After their breakup, Chase attempts to rape Kya, who fights him off and escapes. However, Kya knows that Chase is the kind of man who "needs the last punch" and will likely retaliate; for the first time, she feels unsafe in her marsh home.
Kya goes out of town to meet her editor, Robert Foster, and when she returns, Jumpin' informs her that Chase died by falling off the fire tower, though suspiciously, the police found no footprints or fingerprints at the scene. After finding wool fibers matching Kya's hat, receiving tips that the shell necklace Kya gave Chase was missing from his corpse, and hearing eyewitness testimony that Kya boated to the fire tower the night of Chase's murder, the police arrest Kya. She spends two lonely months in prison before being tried for murder.
Nearly the entire town attends Kya's trial, believing she is guilty and wanting for her to receive the death penalty. Tom Milton, an experienced and respected lawyer, comes out of retirement to represent Kya. Through cross-examination, Tom Milton proves that the prosecution's case is circumstantial, speculative, and prejudiced. Kya is acquitted and returns to her marsh, where she spends the rest of her life with Tate and her brother, Jodie. Eventually, Kya dies after a successful career as a wildlife writer; "long lines" of people attend her funeral, revering her as the legendary "marsh girl."
Living alone, Tate finds a hidden box in Kya's floorboards. Inside are published poems written in Kya's handwriting and Chase's shell necklace, proving that Kya killed Chase. Tate returns the shell necklace to the sea and burns Kya's poems, allowing the marsh to "keep her secrets deep."
