When Carrie was accused of brutally murdering her husband's lover, she denied it. She denied it again when they found her blood inside the victim's house, again when they put her in front of a jury, and again when they sent her to prison. Now three years into her fifteen-year sentence, gradually losing hope and separated from her pregnant daughter, she is still maintaining her innocence. Tess is the only employee of Innocence UK, a charity that helps clear the wrongfully convicted, and which accepts Carrie's case. But can she trust Carrie? Meanwhile, in order to find the truth, Tess must face her own past lies, all the while managing the naive junior investigator assigned to be her shadow.