The Darkness

The player takes the role of Jackie Estacado with the story presented as a future-narrative on the present events observed by the player. On the eve of his 21st birthday, Jackie is targeted for assassination by "Uncle" Paulie Franchetti, a New York Mafia boss, following a failed task to retrieve money for the latter. While hiding in a cemetery bathroom, the Darkness (voiced by Mike Patton), an ancient demonic force that has inhabited his family for several generations, awakens within Jackie and slaughters the remaining mobsters, with the benefit of Jackie becoming the possessor of seemingly unholy demonic abilities that work only in the dark. Using these powers, Jackie proceeds to destroy Paulie's business by killing his biggest drug peddler, Dutch Oven Harry, and burning down the slaughterhouse where he stores his money. In retribution, Paulie and his main enforcer, Captain Eddie Shrote of the New York City Police Department, kidnap Jackie's girlfriend Jenny Romano. They take her to the orphanage where Jackie and Jenny grew up and murder her in front of a powerless Jackie, who is unable to save Jenny due to the Darkness deliberately restraining him.

Jackie then commits suicide out of sheer emotional stress, finding himself in the Otherworld, the realm of the Darkness, which is home to patchwork undead beings in World War I outfits fighting each other and physical manifestations of the Four Horsemen. He meets his great-great-grandfather Anthony Estacado, who reveals that it was he that brought the Darkness into the family and tells Jackie how to free himself of the Darkness by invading the castle in the Otherworld and facing the Darkness there. Jackie is interrupted in his journey through the Otherworld and brought back to the living.

Once he recovers, Jackie determines that he must dispose of Captain Shrote before he can face Paulie. After failing to kill Shrote at his apartment, Jackie steals a briefcase containing illicit goods in Shrote's ownership from a Turkish bath that is used as a front by his corrupt police officers. Jackie rigs the briefcase with an explosive and sets up a meeting with Shrote at Trinity Church. Jackie heads to the meeting to kill Shrote, but he is instead captured by his men following a shootout. After overhearing about a shipment of drugs that a Chicago mob is entrusting to Paulie to handle from one of Shrote's officers, Jackie triggers the explosive, killing Shrote and his men along with himself. Jackie re-awakes in the Otherworld and lays siege to the Darkness's castle with Anthony's help. Anthony is mortally wounded in the attack, but before he can tell Jackie the last steps needed to free himself from the Darkness, the spirit pulls him away.

Jackie faces the Darkness and surprises him by willingly being taken by the Darkness's power, allowing him to fully control the spirit back in the real world. However, the Darkness tells him that while he has control now, each time Jackie takes a life, he will become more consumed by the Darkness. He lays an assault on the drug shipment, causing Paulie to flee to the safety of a lighthouse mansion for fear of retribution from the Chicago mob. Jackie takes advantage of a solar eclipse to raid the mansion and finally kill Paulie. The Darkness revels in Jackie's murderous spree, and fully envelops Jackie.

In the epilogue, Jackie finds himself in a dream, lying on a park bench in Jenny's arms. Jenny explains that they are only allowed a few minutes to be together one last time to say goodbye. Jackie tries to ask how, but Jenny just quiets him, allowing them to enjoy the last moments together before Jackie wakes back up with the screen fading to black.