Main •
Stana Katic as Special Agent Emily Byrne, a former FBI special agent who disappeared while hunting one of Boston's most notorious serial killers and was presumed dead, but returns six years later with no memory of her abduction. While struggling to rebuild her life and unravel the mystery of her disappearance, she becomes the prime suspect in a string of shocking new murders, and becomes a fugitive. Kalina Zaharieva plays a young Emily. •
Patrick Heusinger as Special Agent Nick Durand, Emily's husband and fellow FBI special agent who suffers with guilt that he stopped looking for Emily. He attempts to balance his life with Emily's return and his resurfacing feelings for her against his new marriage to Alice. After Emily goes on the run, his belief in her innocence crumbles and, after his family is endangered, he relentlessly hunts her down. •
Cara Theobold as Alice Durand (seasons 1–2; guest season 3), Nick's new wife and Flynn's stepmother. Alice attempts to remain graceful and kind, but her behavior towards Emily becomes increasingly harsh in the chaos after her return, believing that she is losing Nick's affection and that Emily is a danger to Flynn. •
Neil Jackson as Jack Byrne, Emily's older brother, a former surgeon who lost his job and medical license due to his alcohol addiction. In the first season, he is a medical supply salesman. In the second season, after getting his medical license back, he starts working as an EMT and a paramedic working towards being reinstated as a medical doctor. •
Angel Bonanni as Detective Tommy Gibbs (seasons 1–2), an ambitious and relentless Boston Police detective in charge of investigating Emily for murder, who later teams up with Nick to hunt Emily down. •
Bruno Bichir as Dr. Daniel Vega (season 1), an FBI psychologist and profiler, who works with Emily to heal her psychological wounds and find her abductor. •
Paul Freeman as Warren Byrne, a retired Boston Police officer and Emily's adoptive father. •
Ralph Ineson as Special Agent Adam Radford (season 1), the political and career-minded special agent in charge of the FBI's Boston field office, and Nick and Emily's boss. While he cares about Emily, he later coordinates a manhunt for her after she goes on the run. •
Christopher Colquhoun as Special Agent Derek Crown, an FBI special agent and colleague of Emily and Nick, who is later promoted to special agent in charge of the office after Radford's death. He is later demoted and replaced by Julianne Gunnarsen, but is re-promoted to the position near the end of the series after Gunnarsen is arrested for corruption and murder. • Patrick McAuley as Flynn Durand, Emily's son with Nick, who has almost no memory of his mother and so is estranged and uncomfortable around her, although they gradually build a relationship. •
Matthew Le Nevez as Special Agent Cal Isaac (seasons 2–3), an FBI special agent and colleague of Emily and Nick, as well as a rugged former Navy SEAL, who becomes Emily's similarly haunted, loyal and empathetic counterpart. •
Natasha Little as Special Agent Julianne Gunnarsen (seasons 2–3), a new member of the Boston Field Office who is regarded as the FBI's best profiler, and joins the office after a lethal terrorist attack impacts Boston. She is later promoted to replace Crown as Special Agent in Charge of the office. She is eventually arrested near the end of the series for multiple acts of corruption, including Alice's murder, after her connection to an international crime ring is uncovered.
Recurring •
Lydia Leonard as Logan Brandt / Laurie Colson (season 1; guest season 2), a journalist investigating Emily. •
Richard Brake as Conrad Harlow (season 1), a reclusive wealthy banker and prime suspect in the serial killer case Emily was investigating before her disappearance. While the FBI was never able to make a case against Harlow as the serial killer, he is convicted of Emily's kidnapping and murder and sent to prison. Six years later, Emily's discovery results in his release. •
Hugh Quarshie as Dr. Semo Oduwale (season 2), Flynn's therapist and Alice's mentor. •
Geoff Bell as Colin Dawkins (season 3), a fixer working for an international crime syndicate to retrieve incriminating files by any means necessary. •
Josette Simon as Rowena Kincade (season 3), Emily's former FBI instructor. •
Ross O'Hennessy as Armstrong (season 3), Cal Isaac's former unit leader in Afghanistan ==Episodes==