Vivian Carter commits a crime on purpose to infiltrate Dusk Prison, all in a desperate bid to save her younger sister Lily Carter. Bearing a full-back tattoo of the prison blueprint, she persuades her cellmate Irene Locke to form an alliance and plan a prison break. The two navigate countless perils and gradually develop deep affection for each other amid despair.
On the eve of their jailbreak, Lily chooses to fight back against the tyranny, only to be shot dead by Cayden Thorne. Shattered by her sister’s death, Vivian is gently healed and comforted by Irene. Two souls trapped in hopeless darkness join hands to lay meticulous schemes for escape and revenge.
Breaking through layers of barriers and deadly traps, they finally take down the villains, break free from the prison walls, and expose the bloody crimes of capital power to the public. At last, they walk hand in hand toward eternal love and freedom.