Blue is a sixteen-year-old girl who lives with a family of clairvoyant women in Henrietta, Virginia. As a "booster," she amplifies the supernatural abilities of those around her, though she lacks psychic vision herself. She purposefully cultivates an eccentric, colorful appearance to distance herself from what is considered normal. She carries the heavy burden of a lifelong prophecy predicting that if she kisses her true love, he will die.

Richard Gansey, usually just called Gansey, is a wealthy student at the elite Aglionby Academy. Driven by a childhood near-death experience involving a hornet attack, he feels an intense need to justify his survival by leaving a meaningful mark on the world. He obsessively leads a quest to find the tomb of Owen Glendower, a mythical Welsh king rumored to grant a wish to whoever wakes him. Despite his immense privilege, he struggles to understand the financial realities of those outside his social class.

Adam is a hardworking scholarship student at Aglionby Academy who comes from a low-income background. Unlike his affluent friends, he works multiple part-time jobs to pay for his education and strives to escape his abusive home life in a local trailer park. He desperately seeks independence and views the quest to wake Glendower as a way to gain royal favor and permanently change his circumstances without relying on charity.

Ronan is the fierce, protective bad boy of the group, known for his buzzed head and confrontational demeanor. Beneath his aggressive exterior, he harbors intense guilt surrounding his father's death. He struggles academically at Aglionby and uses his hostile attitude to keep others at a distance, hiding a surprising tenderness for the vulnerable things he cares for.

Noah is a quiet, elusive member of the group who frequently hovers on the periphery of their activities. He tends to fade into the background, often missing classes and seemingly unbothered by ordinary teenage concerns. His connection to the group's search and the local supernatural phenomena proves deeper than it initially appears.

Neeve is Blue's aunt and a famous psychic who has capitalized on her clairvoyant abilities to gain wealth and public influence. She visits her family in Henrietta under the guise of an innocent trip but harbors darker ambitions. She seeks to harness the energy of the local ley line to increase her own power, ignoring the potential dangers of her rituals.

Whelk is the Latin teacher at Aglionby Academy who lost his family's vast wealth and status due to his father's crimes years ago. Desperate to reclaim his former privilege, he quietly obsesses over finding the ley line and waking Glendower. He hides his ruthless ambition behind a veneer of academic respectability.

Maura is Blue's mother and a gifted clairvoyant. She works from her home providing psychic readings alongside her friends. She maintains a somewhat hands-off parenting style, allowing Blue the space to make her own choices while keeping a watchful eye on the prophecies surrounding her daughter's future.

Persephone is one of the clairvoyant women who lives and works with Blue's family. She has an airy, perceptive nature and helps provide readings for clients seeking supernatural guidance. She is supportive of Blue and encourages her to actively investigate the mysteries she encounters.

Calla is a pragmatic and sharp-tongued psychic who lives with Blue's family. She provides readings alongside Maura and Persephone and does not hesitate to speak her mind, especially when she senses hidden truths or dangers surrounding the clients who visit their home.

Adam's father is a bitter man who lives in a trailer park in Henrietta. He deeply resents Adam's friends and his attendance at the elite Aglionby Academy, viewing his son's ambition as an insult to their poverty. He regularly uses physical violence to try and maintain control over his son's life.

Ronan's older brother is a primary source of tension within the Lynch family. The death of their father drove a wedge between the two siblings, leading to frequent physical altercations and deep-seated mutual resentment.

Chainsaw is a baby raven that Ronan cares for. The bird serves as a calming presence for Ronan and hints at the magical mysteries surrounding the local ley line and the mythological Glendower.