Rocco's story is one of love and revenge. His tale starts when he is blamed for doing a poor job for his new employers and is forced to flee. When they murder his beloved Barbara, Rocco becomes blind with revenge and mercilessly hunts down her assailants. And he doesn't stop until the whole city of Vienna is set ablaze.
Rocco Romano never intended to break his promises, but when the burnt-out legendary mercenary refuses to kill a woman named Rosa Leyen, he is summoned to the Goldschild headquarters at the Maîtresse.
In Rocco's presence, a clandestine meeting takes place consisting of Nathaniël and Konstantin Goldschild, Michael Splindegger, and Manuel Kronenberg. After overhearing their plan to game the financial system, he is held responsible for his shortcomings, gets branded by an iron on his face and is taught a lesson in obedience.
Nostalgic of the good old days and weary of living, Rocco feels ready to to drown his pain and sorrows at the Maîtresse, but instead rekindles with his old flame, Barbera Engl.
Rocco and Barbera fall hopelessly back in love, catch up on old times and spot Rosa, who is being kept, seemingly uncomfortable, by Reinhold Lehner.
Quickly infatuated with Barbera again, Rocco talks and waltzes, until he loses sight of her. He then runs into Rosa Leyen, and tells her to run for her life. Another assassin, Joseph Einzel, spots him doing so.
Having sobered up, Rocco gathers all his courage and asks Barbara to marry him: To run away and never turn back. Barbera agrees on one condition: that Rocco helps her sister, Camilla Engl, who she believes is in trouble.
Rocco decides to help out Barbera's sister, but after he encounters Konstantin Goldschild on the RingStrasse, he and Barbara are forced to flee, taking refuge at an ally behind the Preacher's Chair until the threat is cleared.
Rocco takes Camilla with him against her will until two uninvited gunslingers corner them and hold them at gunpoint. When a police officer joins in, they all find themselves in a confrontation with no winnable strategy.
Barbara gets murdered. In an act of violent interrogation, Rocco finds out Konstantin Goldschild and Augustin Salvatore del Tore, an old acquaintance, are to be held responsible.
With the untimely death of his beloved Barbera still bitter in his mouth, Rocco heads to the Wicked Witch in search of answers. But due to the blindness of his revenge, he gets into a fight with a burly fellow named Moritz. Barely alive, Rocco manages to beat the man into a pulp, to which a fight broker by the name of Hugo Léon approaches him with an offer. In a showing of fighting cards, Rocco spots Joseph Friedlander, the man who branded him. He decides to follow Hugo to the St. Marx Slaughterhouse for a proposed bare-knuckle fight.
The St. Marx slaughterhouse soon becomes the theatre of a veritable hunting scene as Joseph is captured, and every other rival desperately attempts to keep one step ahead of Rocco.
All are dispassionately murdered at the St. Marx slaughterhouse, except for Joseph, who confesses to Rocco that Konstantin can be found at palace Belvedere that night.
While holding Konstantin Goldschild responsible for the murder of Barbera, Rocco rides to Mehmed, an old friend, to cash an old check. Mehmed provides Rocco with a dragon-shaped flame thrower, one of the world's most carefully guarded secrets.
Ready to watch the world burn, Rocco heads to Palace Belvedere. On his way there, he obtains a plague doctor's masque and is able to attend the masked ball unnoticed. After finding out the whereabouts of Konstantin, he confronts him with his deeds and unleashes a maelstrom of fiery destruction.
While Belvedere is burning in the background, Rocco is cornered by another old friend, Augustin Salvatore del Torre, due to the enormous price on his head. Someone knocks him out unconscious.
Two days pass until Rocco wakes up, wounded, tortured, and imprisoned in some unknown basement. Augustin tells him he is being kept as bait to lure Nathaniel, who has betrayed Augustin on a business agreement. Rocco, however, manages to escape his bonds and take any soul brave enough to enter the underground room until he has no choice but to step out.
Forced to surrender, Augustin holds Rocco at gunpoint until Karl Weisthor, Marshal of the Austro-Hungarian Imperial Court, barges in. He is there to arrest Rocco on behalf of Michael and the clandestine members. After Rocco tells him to run off, Rocco becomes a witness to the hell on earth that is the battle between Karl's Imperial army and Augustin's Garduña.
Rocco survives, and after interrogating another survivor, he finds out Rosa Leyen is still alive. Rocco set out on a mad journey to rescue Rosa.
Rocco wakes up at Gottfried's place, without his surgically removed left arm.
Rosa then tells Rocco and the others about the scheme of the century. Rocco comes up with an idea to turn the tables.
Rocco leads the rebellion to free Austro-Hungary from the tyranny of the clandestine empire.
During the violent revolt, Rocco and the thousands of rebellions successfully sway the soldiers to lay down their arms. On their way to the gold deposits, Rocco dies a terrible death as a result of his injuries. Despite the horror, he is relieved to have fought the good fight and imagines seeing Barbera again.