Mardi Gras in New Orleans, and Jim and Artie are wearing masks at a hotel, disguised as Don Juan and MacBeth. Jim has received instructions to meet an attractive woman and they separate and start circulating. One woman approaches Jim and he offers her a rose, but when she doesn’t respond per the agreed signal, Jim moves on. Meanwhile, a man dressed as Cassius dons a mask and enters the crowd behind Artie. Another woman approaches Jim and asks for a rose, and gives him a white rose in response. Meanwhile, a woman disguised as a slave girl offers Artie a glass and he realizes the number 443 is written at the bottom.
Jim’s mystery woman leads him through the streets and says that they’re being followed, and tells him to kiss her like he means it. Before she can explain, someone shoots at them, missing and hitting a nearby gaslight. They duck into the bushes and four men dressed as clowns pursue them. The woman leads Jim down an alley where a one-eyed man is waiting to help him into the sewers. While the woman runs off, the killers shoot the one-eyed man. He closes the manhole cover and leads Jim down the tunnels before collapsing. As Jim looks around, a paraplegic man in a Union soldier’s uniform wheels himself in on a cart. He demands to know why Jim is there, but Jim says they should look after his guide. The newcomer identifies him as Corporal Hayden as several other men enter the intersection. One is blind, two are missing an arm each, and two wear masks to cover their scarred features. All of them are armed, and the first man declares Hayden dead and covers him over. The blind drummer plays and all six men salute their fallen comrade.
Artie goes to a manor at 443 and enters through the gate, and finds the Cassius from the hotel and two of his soldiers waiting for him. When they advance on him, Artie uses his Hamlet skull containing a Roman candle as a distraction to slip out into the crowd, grab a new costume, and get away.
The woman arrives as Jim introduces himself. The leader, Major Hazard, wonders who invited him and the woman, his daughter China, explains that she brought Jim there. Jim says that China informed him that Hazard knows where Colonel Tacitus Mosely can be found. Hazard tells Jim that he’s wasted his time, and Jim notes that Mosely was a Confederate officer in charge of the Susquehanna Prison Camp during the Civil War, and who tortured his prisoners and then disappeared once the high command found out what he was doing.
Jim wonders why Hazard won’t help bring them to justice, and the ex-major introduces the other members of his surviving regiment: Maberly, Cope, Steinlen, Carter, and Quist. Hazard wants the pleasure of disposing of Mosely himself, but China points out that her father spent years following up rumors. Now that Mosely knows they’re after him, they’ve been forced to survive in the sewers. Hazard believes that it’s all worthwhile, but China insists that they can’t possibly win against Mosely and his army of private killers. She doesn’t care as long as she can keep her father and his friends from throwing their lives away. She shows Jim a wall with the names of the five other men who survived, but have since died trying to kill Mosely. Jim says that the goal of a soldier is to kill the enemy rather than die, and asks for two days to find Mosely and bring him to justice. Hazard considers and then has China bring him a box. The major explains that Mosely has become a squire and runs a sugar plantation under the name of Dennis Craig, and gives him a photo of Mosely after he has had his face changed.
At the Wanderer
, Jim and Artie meet with Colonel Henderson. Artie confirms that the Cassius who confronted him is Mosely, and Jim says it’s time to bring him in. However, Henderson says that they can’t go barging into the plantation until they’re sure of his identity. He admits that it could take weeks and Jim warns that if they don’t hurry, Hazard and his men will sacrifice themselves trying to kill him. Henderson explains that a special court has been prepared to bring Mosely to justice, and officially they are to sit tight until they have the files from Washington. However, as he leaves, the colonel stresses “officially.” The agents then go back to work charting a course to Mosely’s plantation.
That night, Jim rides up to the plantation gates and starts to go in. Three of Mosely’s Cajun men approach him with guns, and don’t believe Jim’s claim that Mosely is expecting him. They tell him to leave before they lose their temper, and their leader shoots at Jim’s feet. When they attack Jim, he defeats them after a brief fight and rides up to the manor. Two men come at him from either side while the Cajuns from the gate recover and approach. The door behind Jim opens and Mosely comes out with a gun. He demands to know what Jim wants and the agent mentions Susquehanna. Mosely invites him in and Jim cheerfully tells him that he’s under arrest and calls him Mosely
As Mosely pours drinks, he complains about how Jim is everything that he despises. When he goes to close the door, Jim switches glasses. When Mosely comes back, he asks Jim to prove who he is, and refuses to go to Washington with him. As they talk, Jim realizes that he’s been drugged and passes out, and Mosely explains that both drinks were dosed with belladonna. However, he has worked up a tolerance over the years.
When Jim wakes up, he’s tied to a chair in front of a grandfather clock. A wire has been attached to the hour hand, a wire extending to the trigger of a weight suspended over a bottle filled with liquid. Mosely comes in and explains that the bottle contains naphtha, and the smaller jar suspended within holds nitroglycerine. He figures that other agents are coming and it will be his remains that are found in the burning house. Once Mosely leaves, Jim gets to his sleeve derringer and shoots the pendulum on the clock, stopping it. Artie, disguised as Mosely, comes in through a hidden passageway that they discovered from the blueprints and frees his partner. Mosely comes back and Artie steps out to distract him while Jim applies a nerve pinch to knock him out. Artie administers a sedative and they place Mosely inside of the grandfather clock’s cabinet. Once Mosely’s men load it aboard, Jim drives off with it in a wagon while Artie promises to follow.
Back at the train, Jim checks on the unconscious Mosely, but is then caught by surprise when China, Hazard, and his men come in and capture the agent at gunpoint. Hazard explains that they will hold their own trial at the court martial hall of the Susquehanna POW camp. To stop them, Jim will have to kill them. Jim reluctantly turns over his gun and casually picks up a newspaper to fan himself. As Hazard prepares to shoot Jim, he pricks the paper with a pencil. China objects, suggesting that they made need Jim. Hazard asks if Jim agrees, and Jim says that he can act as defense counsel for Mosely. Amused, Mosely and the others agree and take away Jim and the grandfather clock holding Mosely. As they leave, Jim drops the newspaper on the couch.
Later, Artie and Henderson arrive at the train and wonder where Jim has gone. Artie figures that his partner left some word, picks up the newspaper, and finally notices the Morse code dots that Jim left earlier. The message says that Jim has gone to Susquehanna and Artie wonders why everyone would suddenly be going there.
Hazard and his men bring Jim and Mosely to the deserted camp. As Hazard’s men take the unconscious Mosely into the court martial hall, Jim looks around at the whipping posts, the water tower, the gallows, and the viewing galleries holding eight chairs. He then goes inside to where Hazard has assembled a makeshift courtroom. Mosely wakes up and tries to run, but Quist and Carter stop him. Jim moves for a directed verdict of not guilty and Hazard asks him to explain why they would possibly do that. The agent says that he’s moving for a dismissal on the grounds of fraud, and says that the accusing witnesses are lying. Jim punches Quist and Carter, knocking off their masks and revealing that they’re unscarred. Hazard feigns astonishment and invites Jim to continue.
The “blind” Steinlen removes his glasses to reveal that his eyes are intact, while Maberly and Cope have their supposedly missing arms. Hazard finally stands up out of his trick platform and congratulates Jim on seeing through their charade. Jim points out that the gallery and the court martial chamber had eight seats, and remembered how Mosely had seven hand-picked assistants. The other men on the casualty lists were fake names, and the eight seats were for Mosely and his seven men to enjoy the tortures of the prisoners. Counting the dead Hayden, the total comes to eight. A shocked China draws a gun and aims it at Jim, who invites her to ask her father for the truth. After the moment she puts down the gun and leaves.
Hazard and his men strap Jim and Mosely to the posts and prepare to whip them. The major thanks Jim for delivering Mosely to them, and Mosely insists that he doesn’t have what they want. Hazard doesn’t believe him and invites Jim to speculate as to why they want Mosely. The agent figures that it involves money and Hazard explains that a chest containing one million dollars in gold was delivered to Susquehanna in the closing days of the war. Mosely hid the money in the camp and skipped before the advancing army arrived, and they plan to torture him until he reveals where it’s hidden.
Artie chooses that moment to enter the camp, disguised as an Englishman with a divining rod. Hazard prepares to shoot him until Artie says that he can also find gold. Using some sleight of hand, Artie plants a gold nugget and then “finds” it. While the others start digging, Artie complains that the metal in their guns is interfering with his readings. They hastily put all of their weapons to the side and Artie goes to the posts, and then uses the electrodes inside of the divining rod to free Jim. He takes on Hazards’ men while Hazard goes for the guns. The major and Artie exchange fire and Hazard climbs the water tower while Artie grabs the other guns. As Jim disposes of his men, Hazard prepares to shoot Jim and Artie tosses a gun to Jim. Jim shoots Hazard, who falls and pulls on the water tower’s chute cord. The gold nuggets pour out of the tank, burying Hazard in the gold that he sought. China runs out and goes to her dead father, and Artie figures he finally got the gold he was after. Jim frees Mosely for his trip to Washington.
Later at the Wanderer
, Henderson tells Jim and Artie that now that everyone has been brought to justice, Susquehanna will be converted into a site for parks and homes. The jury recommended parole for China since she didn’t know what her father and his men were doing. Artie explains that after he realized Jim was headed for Susquehanna, he did his research and confirmed that the million dollars in gold had gone missing and was never recovered. Jim offers a victory toast and the three men drink to their triumph.