In a letter to the Continental Congress, George Washington [Kelsey Grammer] recommends Brigadier General Benedict Arnold [Aidan Quinn] for promotion to Major General, highlighting a string of daring feats that mark him as a pivotal Patriot. Washington recalls Arnold’s bold invasion of Canada through the Maine wilderness, a campaign he likens to Hannibal crossing the Alps. He notes that if Arnold hadn’t been wounded at the Battle of Quebec, Canada might now be the 14th State. He also praises Arnold’s feat at the Battle of Valcour Island, where, despite losing all his ships, he managed to halt a northern British invasion. Washington then reveals that he is also aiding General Horatio Gates in fending off another northern threat. The narrative frame presents Arnold as a celebrated war hero, one whose hard-won victories shape the course of the Revolution.
At Saratoga, Horatio Gates presses Arnold to retreat, pushing a political reshuffle that elevates Gates to First in Command of the Northern Army. Arnold, however, reminds Gates that they share a joint command and cannot be treated as a subordinate. The standoff erupts into action: Arnold refuses to bow to the order and leads the Northern Army to a decisive victory, even at the cost of a leg wound. The victory forces British General Burgoyne to surrender, but Gates claims the credit for the win while Arnold endures treatment and faces the painful choice about his leg. Arnold resists amputation, and after the battles Gates moves on to command the Southern Army while Arnold returns home for a period of recovery.
Months later, Arnold is summoned by George Washington to Valley Forge, where he is welcomed back as a ranking Major General and steadily restored to active duty. Back in Philadelphia, the British are secretly planning their next move toward New York City. John André [John Light], a captain in the British Army, promises Peggy Shippen [Flora Montgomery] that he will return for her, weaving personal and political loyalties together as the war tightens its grip on Philadelphia. Arnold arrives in the city because Washington appoints him Military Governor, with Major David Franks at his side as his aide-de-camp. The Pennsylvania Governor, Joshua Smith [Mark Lambert], tries to intimidate him, but Arnold holds his ground in a display that earns him the respect of the local militia. He toils to secure wagons for the army, negotiating with a merchant to profit from supplies and logistics, and in the process throws a lavish party to celebrate the city’s evolving dynamism. Peggy Shippen, watching from the sidelines, is intrigued by this powerful, if controversial, military figure.
Judge Shippen [John Kavanagh], Peggy’s father, is deeply wary of Arnold’s self-righteous Puritanism, his rough industrial background, and the smear campaigns waged by newspapers that attack his character. He makes his disapproval known and demands a court-martial to clear Arnold’s name, a request Arnold travels to Washington to make. After a difficult exchange, Arnold marries Peggy, but the moment is marred by mounting tensions: a mob gathers at Mount Pleasant, Arnold’s home in Pennsylvania, furious at both his marriage and his meteoric rise. To protect his family, Arnold dispatches Major Franks to bring Continental soldiers to shield his house, his sister Hannah Arnold, his sons Benedict Arnold VI, Richard Arnold, and Henry Arnold, and Peggy. When Franks returns, he reveals that Washington won’t send troops and instead sends Arnold a bill for the wagons used—an emblem of how little value the Congress and Washington appear to place on his sacrifices.
Peggy convinces Arnold that he and his family are undervalued and proposes a more drastic path: defect to the British Army. She reaches out to André, who has now become a major and adjutant general, to relay Arnold’s willingness to switch sides. André relays instructions to test the fidelity of Arnold by demanding the capture of West Point. Arnold sends back his terms, and the story naturally pivots toward a dangerous plan that could alter the war’s outcome. Back at the court-martial, Washington rebukes Arnold for war profiteering, signaling a growing chasm between the general and the man. It becomes clear that Arnold is no longer trusted by the Continental leadership, while the idea of command continues to tempt him with the possibility of regaining esteem if he can maneuver West Point into British hands.
Washington offers Arnold a way back—command of the Left Wing of the Main Continental Army—if he will return to active service, but the lure of greater authority and the promise of prestige pull Arnold toward a fateful decision. Peggy presses him to seize the opportunity, arguing that Congress and Washington cannot truly value his sacrifices. The tension intensifies until Washington grants his request, even as the marriage strains under the shadow of treason.
Six months later, Arnold and Peggy live in close proximity to West Point, their infant son Edward Arnold in tow. Arnold meets with Joshua Smith [Mark Lambert], who informs him that André will meet him aboard HMS Vulture. Peggy warns him that danger lurks if he betrays the army, noting that a knighthood or title could come with such a choice. André arrives, and the two men work out a plan to seize West Point, though a cannon volley forces André to land to continue the discussion. He is seized by local authorities; Jameson, a colonel, takes news of “Anderson’s” capture back to Washington, hinting at the unraveling of Arnold’s scheme. The messenger delivering the West Point plans reaches Washington, who declares with mounting horror, “Arnold has betrayed us! Apparently, he was about to deliver up West Point to the enemy with all of us! If our greatest warrior is a traitor can anyone be trusted?!” The conspirators—Franks, Smith, and Joseph Calhoon—are arrested, while the garrison hastily repositions its defenses, with the cannons returned to place and the fort readied for a British assault.
The moment of reckoning arrives as Arnold—in league with the British—offers himself up to André. Sir Henry Clinton, hearing the plan, refuses to surrender a deserter, while Arnold deflects the rebuke with a pointed retort that underscores the internal conflict roiling him: “What you think you are and what the world assigns will always be at odds.” André is subsequently executed by hanging, marking the tragic end of the conspiratorial arc that began with ambition and culminated in treachery.
Eighteen years later, the once-celebrated Arnold and Peggy are living in the United Kingdom, where he confronts a lifetime of exile and infamy. He comes to the stark realization that his name will forever be etched in granite as one of the Revolution’s most infamous traitors. The epilogue notes that Arnold dies three years after that realization, and his only monument at Saratoga bears a sparse tribute—“In memory of the most brilliant soldier of the Continental Army who was desperately wounded in this spot winning the most decisive battle of the Revolution and for himself the rank of Major General.”
