Caroline is a twelve-year-old girl living on Water Island in the US Virgin Islands. Born during a powerful storm, she is told she carries a curse, but her main concern is finding her mother who vanished over a year ago. Caroline possesses the secret ability to see spirits, making her feel alienated from her peers at her Catholic school on Saint Thomas. She is highly self-aware and fiercely determined, often hiding her vulnerability behind a tough exterior.

Kalinda is a confident new student at Caroline's Catholic school. Originally from Barbados, she temporarily lives on Saint Thomas with her father. She wears her hair in thick locks and instantly wins over the class with her quick wit. Unlike the other children, Kalinda brings a sense of imagination to Caroline's life and shows distinct empathy for outcasts.

Doreen is Caroline's beautiful mother who disappeared from Water Island over a year ago. She has a rough, low singing voice that Caroline loves. She used to send her family postcards from travels around the world. Though physically absent in the early story, Doreen's memory heavily influences Caroline's everyday actions.

Caroline's father is a quiet man raising his daughter alone on Water Island following Doreen's disappearance. He works on the neighboring island of Saint Thomas and has stopped using his blue boat. He struggles to communicate effectively with Caroline and often fails to understand her emotional depth.

Anise is the lead bully at the Catholic school Caroline attends. She holds significant social power over her classmates, often initiating cruel rumors and physical altercations. With her straight-ironed hair and painted nails, she flaunts a level of maternal care that Caroline lacks.

Miss Loretta Joseph, known as Miss Joe, is the principal of the Catholic school on Saint Thomas. She is an independent, unmarried Black woman who fixes her own pickup truck. She demonstrates deep empathy for Caroline's feelings of isolation and tries to offer guidance by sharing literature.

Marie Antoinette is a quiet, white classmate at the Catholic school who is part of Anise's social circle. Though she associates with the bullies, she rarely speaks and watches Caroline with sympathetic hesitation. She lacks the courage to stand up to Anise, reflecting a passive response to the toxic school environment.

The Woman in Black is a mysterious spirit appearing to Caroline during moments of intense isolation. She is described as having skin blacker than darkness itself, with eyes shining like two full moons. Her silent presence terrifies Caroline, who begins to suspect the spirit holds the key to uncovering her mother's whereabouts.

Missus Wilhelmina is a teacher at the Catholic school on Saint Thomas. She is openly hostile toward Caroline, regularly targeting her for physical discipline and verbal degradation. She enforces arbitrary rules and fails to stop the intense bullying occurring in her classroom.

Mister Lochana is a neighbor on Water Island who operates a small speedboat. He offers cheaper rides to Saint Thomas than the standard ferry, providing crucial transportation for island residents. He previously rescued Caroline from drowning when she fell overboard in her Sunday clothes.

Bernadette is a young girl visiting Water Island with her mother. She stays in a rental house near the scorched hill. She bears a striking physical resemblance to Caroline's father and confronts Caroline with uncomfortable claims about their shared family ties, adding tension to Caroline's home life.

Kalinda's father is a quiet carpenter living on Saint Thomas. He lost his hearing at age eighteen, forcing him to abandon his dream of becoming a guitarist. He relocated from Barbados to stay with his sister while searching for steady work to support his daughter.

Mister Thompson is Kalinda's neighbor on Saint Thomas. He spends his nights playing the accordion and singing outside. He unknowingly provides a comforting soundtrack for Kalinda, who sometimes sneaks out to fall asleep on the concrete while listening to his music.