The narrator, Mike Noonan, a bestselling novelist, suffers severe writer's block after his pregnant wife Jo suddenly dies of an aneurysm. Four years later, Mike, still grieving, is plagued by nightmares set at his summer house in TR-90 (an unincorporated town named for its map coordinates), Maine. He decides to confront his fears and moves to his vacation house on Dark Score Lake, known as Sara Laughs .
On his first day, he meets Kyra, a 3-year-old girl and her young widowed mother, 20-year-old Mattie Devore. Mattie's father-in-law is Max Devore, an elderly rich man who will do anything to gain custody of his granddaughter, Kyra. Drawn to Kyra and Mattie, Mike hires John Storrow, a custody lawyer, for Mattie, and things start looking up. Mike begins to write again, and realizes that Jo's ghost is helping him to solve the mystery of Sara Tidwell, a blues singer whose ghost haunts the house. He also learns that Jo frequently returned to the town in the year before her death, without telling him.
Mike begins having recurring, disturbing dreams and visions, and realizes he shares a psychic connection with Kyra. Max and his personal assistant, Rogette, try to drown Mike but he survives with the help of his wife's spirit. Max unexpectedly commits suicide that same night. Mike sees a pattern when he sees that local inhabitants have names that begin with "K" or "C" and learns how relatives of townspeople have drowned in childhood.
While Storrow and the private detective he hired are celebrating the end of the custody battle, Mattie attempts to seduce Mike. As they are embracing, Mattie's trailer is subjected to a drive-by shooting, injuring Storrow and the detective and killing Mattie. The detective is able to kill the driver and incapacitate the shooter with Mike's help. Mike then grabs Kyra and drives back to his home. The shooter's buddies try to stop them, but refuse to follow him to Sara Laughs. Under the influence of Sara's ghost, Mike is tormented to drown Kyra and commit suicide himself. Jo's ghost prevents him and calls his attention to the novel he has begun to write. In the pages there are clues that lead Mike to discover documents Jo had hidden, among them a genealogy showing Mike's blood relationship to one of the town families.
Several families whose origin lay within the town had firstborn children with "K" names who were all murdered—Kyra, as a descendant of Max Devore, is scheduled to be the next to die. The genealogy also shows that Mike and Jo's child would have been the next firstborn child with a "K" name in the family line. Mike realizes this must be Sara Tidwell's curse for something that had been done to her. He leaves and searches for Sara's grave, stopped by the ghosts of several members of the old families. He learns in a vision that these men had viciously raped and killed Sara, and drowned her son Kito in the lake; all the "K" children who died were descendants of those men. Mike reaches Sara's grave and succeeds in destroying her bones, ending the curse.
Upon returning to the house, Mike discovers that Rogette has kidnapped Kyra. He follows them to the lake, where Mattie's ghost appears and knocks Rogette into the water. Rogette tries to pull Mike in with her, but is impaled by wreckage from the dock. Mattie's ghost says her goodbyes to Mike and Kyra.
The novel ends with an epilogue, revealing that Mike has retired from writing and is attempting to adopt Kyra. His status as a single, unrelated male complicates things, and the adoption has taken longer than anticipated. The outcome of the adoption is left unresolved at the end, but the reader is given hope that it will be positive.