Saint X by Alexis Schaitkin is set on the fictional Caribbean island of Saint X and later in New York City, oscillating between these two settings to develop the novel's narrative.
At the beginning of the novel, readers meet the Thomas family: parents, a teenage daughter named Alison, and her younger sister Claire. They are on vacation at the beautiful resort on Saint X. Alison is a beautiful, vibrant, and privileged young woman who attracts the attention of several men on the island, including two local men, Edwin and Clive. One night, Alison disappears, and her body is later found in a remote location on the island. Edwin and Clive are the primary suspects, but they are released without charges due to a lack of evidence.
Alison's death profoundly impacts Claire, who was only seven at the time of her sister's death. She grows up in the shadow of her sister's absence, her parents never fully recovering from the tragedy.
As the narrative shifts to Claire's adulthood, readers find her living in New York City under the name Emily, trying to distance herself from the past. However, her past catches up with her when she stumbles upon Clive working as a cab driver in the city. This unexpected encounter prompts her to seek a deeper understanding of her sister's death, using it as a means to come to terms with her unresolved grief and the lingering ghost of her sister.
Emily embarks on a quest to befriend Clive without revealing her true identity. Over time, she successfully develops a rapport with him and starts learning more about his past and the fateful night of Alison's death. Meanwhile, Emily keeps digging into her sister's past, reading Alison's diary entries and letters, further deepening the mystery.
The novel's climax comes when Emily confronts Clive with her true identity and asks him directly about Alison's death. Shocked by the revelation, Clive denies killing Alison but admits he was with her on the night she died. He reveals that Alison was extraordinarily drunk and upset, and while he had left her alive and well, he assumes she might have fallen into the water and drowned, unable to save herself due to her intoxicated state.
Saint X concludes with Emily finally gaining closure. She reconciles with the fact that she'll never know the complete truth about her sister's death. However, she also understands that she needs to stop living in the shadow of Alison's memory and make peace with her past. The novel ends with Emily returning to her original name, Claire, as a symbolic act of moving forward.
