Hannah is a 29-year-old bookstore employee living in Scotland who is expecting her first child. Ten years earlier, she was an ambitious, working-class English literature student at Oxford University whose life changed when she discovered her best friend murdered. Now, she faces unresolved trauma and intrusive questions about the decade-old tragedy.

The glamorous and widely envied socialite of Pelham College. April projects immense self-confidence and frequently flaunts her privilege, though she occasionally reveals a generous side to her closest friends. She loves to orchestrate elaborate pranks and acts as the central figure of her friend group.

Hannah's husband and an accountant living in Edinburgh. During his Oxford years, Will was an upper-class student who dated April. He struggles to manage his anger and prefers to keep his emotions tightly guarded, shaped by his strict military upbringing. He views any investigation into the past as a threat to his current family.

Will's best friend from prep school and Oxford, known for his formal wardrobe and traditional manners. He was with Hannah on the night of the tragedy and has since become a successful plastic surgeon in Edinburgh. He maintains a polite, calm presence in Hannah and Will's adult lives.

A former journalism professional and Oxford student who bonded with Hannah over their shared working-class backgrounds. He possesses a cheeky, defensive personality and harbors resentment toward the elitist attitudes of the university. He relies on a wheelchair following a severe stroke five years ago.

A highly intelligent, ambitious mathematician. She is part of the tight-knit Pelham College friend group and later achieves success as a professor at Oxford's Balliol College. She maintains her sharp wit and fierce dedication to her academic career, though the past still affects her.

An English literature professor and academic advisor at Pelham College. He lives across the corridor from Hannah and April's suite and hosts exclusive gatherings for promising students. His casual behavior with young female students pushes professional boundaries and makes some individuals uncomfortable.

An investigative reporter and former colleague of Ryan Coates. He approaches Hannah in the present day with probing questions regarding the official narrative of the decade-old tragedy. He pushes her to reconsider the established facts of the case and aims to produce a podcast exploring the true events.

A porter at Pelham College responsible for mail and security. He is an imposing older man whose overbearing and inappropriate behavior makes students like Hannah deeply uncomfortable during her first year. His recent death in prison sparks renewed interest in the Oxford tragedy.

April's younger sister, who works as a social media influencer. She shares an uncanny physical resemblance to her late sister. She carries forward a modern version of April's glamorous lifestyle while seeking closure for her family.

Hannah's mother, who drops her off at Oxford University for her first year. She occasionally checks in on her daughter, serving as a connection to Hannah's working-class hometown and reminding her of the world outside the academic bubble.