Sade is a new, third-year student at the prestigious Alfred Nobel Academy who was previously homeschooled following multiple family tragedies. She struggles with anxiety, panic attacks, and an unshakable belief that she carries a curse of bad luck. Despite her desire for a fresh start, she is quickly drawn into the mystery of her new roommate's disappearance and refuses to let the case drop.

Basil, commonly known as Baz, is a Brazilian student recognizable by his pink hair and fondness for campus gossip. He hides an illegal pet guinea pig named Muffin in his dorm and relies heavily on his close friendships. When his best friend goes missing, he becomes deeply worried and frustrated by the school administration's apparent lack of urgency.

Persephone is the beautiful, brown-skinned blond deputy head girl at Alfred Nobel Academy. As a leading member of the elite Unholy Trinity, she initially strikes Sade as intimidating, sharp, and unapproachable. However, she demonstrates sharp intelligence and a protective nature beneath her perfectly groomed exterior.

Jude is the wealthy, popular head boy at Alfred Nobel Academy and the captain of the swim team. Known as the school's resident playboy, he is accustomed to getting what he wants and leverages his good looks and privilege freely. He views romance as a game to be won and quickly focuses his attention on Sade.

Elizabeth is a scholarship student and Sade's newly assigned roommate. Though she acts welcoming and introduces Sade to Baz, she appears highly distracted and worried by mysterious text messages on her phone. She vanishes without a trace on Sade's second day at the academy, leaving behind a series of cryptic clues.

August is the deputy head boy at Alfred Nobel Academy and a dedicated member of the swim team. Hailing from a remarkably wealthy family, he carries a reputation as a polite, old-fashioned gentleman. He bonds with Sade over their shared passion for swimming, often encouraging her to join the school's team.

April is the wealthy and influential leader of the Unholy Trinity. As a member of a family that practically bankrolls the academy, she wields significant social power and meticulously controls the guest lists of the most exclusive campus events, such as her joint Halloween birthday party.

Jamila is Sade's late twin sister, whose tragic death continues to haunt Sade profoundly. Although she is physically gone, her memory is a constant presence in Sade's life, manifesting in dreams and intense feelings of grief and guilt that shape Sade's entire worldview.

The pragmatic leader of Alfred Nobel Academy. He is deeply concerned with protecting the institution's prestigious reputation and securing funding, often prioritizing the happiness of wealthy donors over the well-being of scholarship students.

Francis is a fidgety, redheaded student who frequently smells of smoke. He is related to the headmaster and does not hesitate to voice highly misogynistic opinions during classroom debates, deliberately clashing with female students.

The strict and somewhat cantankerous matron of Alfred Nobel Academy. She is fiercely protective of the school's traditional rules and initially scolds Sade for arriving weeks late to the term, monitoring the dormitories with a sharp eye.

Juliette is the talented goalie for the girls' lacrosse team and the third member of the popular Unholy Trinity. She generally follows April's lead in social situations and enjoys the elevated status her friend group provides.

Kwame is a tall, dark-skinned student from Hawking House who rows for the academy's crew team. He regularly seeks out Baz under the guise of needing help with his German homework, despite Baz's poor skills in the subject.