Mara's daughter Sadie is framed by Bryce and sentenced to death. Humiliated in court, Mara takes matters into her own hands—committing armed robbery to get a 25-year sentence and enter Blackwater Prison, where Sadie is on death row. Mara is the architect who designed Blackwater twenty years ago, blacklisted after reporting construction fraud. She has the entire prison blueprint tattooed on her back. Teaming up with Sloane—a gang leader whose daughter Maisie is dying of leukemia—and Sadie, Mara plans an escape: stealing bolts, forging keys, corroding bars with acid, breaking through tunnels under train noise, and hacking Bryce's office to cut the power. Bryce closes in; Sadie attacks him and is sent to solitary. In the final moments, Mara chooses to stay behind and buy time, letting Sloane take Sadie out. Bryce is electrocuted. Sloane tells Sadie her mother may not make it. In the last scene, Mara appears behind an officer, gun to his head—cliffhanger.
