At a cavalry fort in Indian territory Jim is visiting and watches a boxing match with General Titus Ord Baldwin. Baldwin congratulates Lt. Carter on choosing skilled fighters and, and then introduces Jim to Carter and Colonel Rath. As the next match begins, Baldwin explains to Wrath and Carter that the government is unhappy with the recent Indian uprisings in the area and have sent Jim and Artie to find out what is responsible. The general himself is clearly anti-Indian, despite Jim's insistence of what the Indians have contributed to the country.
A sentry outside the fort is standing guard when he hears a woman call him over. However, when he investigates, he discovers that the "woman" is a dummy, and an Indian raiding party knocks him out.
Inside, Baldwin introduces Jim to Oconee, a half-breed and the Indian Department's liaison with the local tribes. Jim isn't convinced that the Indians plan to attack, but Baldwin insists that they will attack. The general's daughter, Aimee, comes in and Baldwin introduces her to Jim. The somewhat ditzy young woman admits that everyone loves her father since he's slaughtered so many Indians.
As the main event begins, Aimee asks Jim to take her outside for some fresh air. He agrees but Carter objects, telling Aimee that she'll miss the main event. She prefers to go with Jim and they go outside, and he wonders how many other soldiers at the fort that she's manipulating. Carter comes out and tells Jim to stay away from the lady, but the raiding Indians unleash a rain of arrows. One kills Carter and another narrowly misses Jim. The agent fires a flare bullet, revealing the three raiding Indians, and he orders them to surrender. As he disarms them, a fourth Indian attacks him. As Jim struggles with all four Indians, he notices a dolphin tattoo on one Indian's right wrist. Aimee grabs Carter's gun and fires, hitting one off the Indians. The Indians run off when Baldwin comes out while the other soldiers and give chase. Artie arrives and examines the Indian that Aimee supposedly killed, and informs his partner that the raider has been dead for at least an hour.
The angry Baldwin calls Oconee out and tells him to warn the local chief Strong Bear, that he'll wipe out the tribes if they launch another raid. Oconee starts to challenge him and the general slaps him, and the half-breed goes for his knife. Jim restrains the general and Oconee tells the agent that he doesn't need his help as he walks away.
When Jim and Artie return to the Wanderer, they find President Grant waiting for them. He's eluded his overly protective aides and comes to see how Baldwin, "The Mighty Titan," is handling the uprising. Grant explains that he and Baldwin were ates at West Point, and that Baldwin is considering a run for the Presidency. The general plans to run on a platform of dealing with the Indian menace, but Grant can't relieve him of command without turning him into a martyr and losing the upcoming election. The agents tell their superior what they discovered, including the "Indian" with the dolphin tattoo, and they figured that someone killed the Indian in advance, and then planted the corpse outside the fort to frame Chief Strong Bear. Grant asks them to deliver a message to Strong Bear asking him to keep the peace no matter how great Baldwin's provocations, but warns the agents that the three previous couriers he sent never returned.
Later, Jim returns to the fort and Aimee invites him to a picnic. While they chat, Artie rides in disguised as Lt. Greeley of the Fifth Cavalry. He distracts Aimee so that Jim can slip away and deliver Grant's message, claiming to be the son of Horace Greeley, editor of the New York Herald. Artie quickly drops the ruse once Jim has left and rides off.
As he rides through the forest, Jim realizes that Indians are following him. Oconee, wearing Indian garb, garb, steps out and demands to know what he wants. Jim explains that he's there to stop a possible war, but Oconee is as eager as Baldwin for combat. They hear a woman's scream and Jim rides to investigate. Several Indians have surrounded Aimee, circling her and slashing at her clothing. Jim warns her to stay still and explains that they're trying to provoke her so they can attack. As Oconee arrives, Jim walks calmly past the Indians, takes Aimee, and escorts her back to her horse. Oconee orders the Indians to leave and admits that he admires Jim's courage. He agrees to arrange for a meeting between Jim and Strong Bear and tells him to be at the Sulphur Spring caves that night at 8. As Jim rides back to the fort with Aimee, she flirts with him and gets him to admit that she's glad she's there.
The disguised Artie goes to Rath's office and intimidates the sergeant in the outer room. As he signs the duty roster, Artie sees a dolphin tattoo on the sergeant's arm, and then tries to go into Rath's office. When the sergeant tries to stop him, Artie blatantly "denies" that he's Rath's nephew, winking, and the sergeant goes to find Rath. Once he's alone, Artie breaks into the office and conducts a search, and finds an Indian costume and wig hidden in a trunk. When he hears Rath coming in, Artie puts everything back and goes outside. When Rath demands to know why Artie claimed he was his nephew, Artie twitches his eye and the sergeant assumes that's the reason he was accidentally winking earlier.
As Jim rides back to the fort, he asks Aimee not tell her father about the attack for fear he'll use it to justify attacking the tribes. Aimee half-teasingly says that she wants to tell the general so that Jim will be decorated, but he convinces her that if Baldwin finds how he met with Oconee, then he'll have Jim sent away. Giving in, Aimee agrees to keep it a secret. However, as they approach the fort, Baldwin rides out with Rath and a platoon to search for the missing Aimee. The general assumes that Jim was taking liberties with his daughter and has his men arrest the agent.
When Artie sees Jim being taken in chains to the stockade, he fakes being drunk and antagonizes Major Lock. The exasperated major finally has Artie arrested for insubordination and taken to the stockade. Once they're alone, Artie tells his partner what he's found and they wonder if Rath is the ringleader or working for someone else. Jim uses thermite to burn through the window bars while Artie assures him that he'll find his own way out.
Aimee comes in to tell Jim that she almost has Baldwin talked into letting him go, but discovers that the agent has escaped. Artie explains that Jim has escaped and that if Aimee alerts anyone, the soldiers will shoot Jim on sight. Aimee agrees to stay silent and leaves, and Artie starts removing his Greeley disguise.
Jim arrives at the Sulphur Spring cave and goes inside, unaware that Indians are hiding in the nearby woods.
Artie switches to a frontiersman disguise and hides the Greeley uniform, and then gets the guard's attention, demanding to be fed. The puzzled soldier assumes that Artie has snuck in and wants a handout, and drags Artie kicking and yelling out of his cell.
Inside the cave, Jim confronts Strong Bear, who is sitting on the floor. The chief says that the raiders are fake Indians, but Jim realizes that someone is nearby speaking. He runs forward and discovers that the "chief" is a dummy and Strong Bear's corpse is hidden nearby. Oconee laughs in triumphant from above as the tribesmen come in. The half-breed yells that Jim murdered their leader and they attack, eventually knocking Jim into a fumarole. He lands on a ledge below, stunned, and they take their chieftain's body and leave.
When Jim recovers, he discovers that the ledge is starting to crumble. As he grabs the edge of the fumarole, Aimee comes in... and starts stepping on his fingers, laughing. Jim falls back onto the ledge and Aimee leaves. With seconds until death, Jim fires a line into the miner support above and pulls himself to safety as the ledge collapses. Artie arrives to help him up and Jim brings him up to speed. After they've compared notes, Artie tells his partner that Oconee as called for a gathering of the tribes at the Indian burial grounds across the lake.
When Jima arrives at the burial grounds, he sees Oconee rousing the tribal chieftains to fight back against Baldwin and his men. Rath and his men come up behind Jim and capture the agent, and the colonel boasts that he'll dispose of Jim and make it look like the Indians did it, further fanning the flames of bloodshed. When Jim tells Rath that he knows about Aimee's involvement, Rather admits that Baldwin has no idea that his daughter is the co-leader of the uprising attempt, and figures that once he comes into office, the general won't care.
As Oconee addresses the chieftains, there's a burst of smoke from Strong Bear's corpse. Artie slips in disguised as Strong Bear and then comes back to "life." He tells the chieftains that Oconee is lying to them and tells them to return to their tribes. Oconee shoots at Artie but the bullets have no effect, and the superstitious chieftains un in terror. While Rath is distracted, Jim attacks him and his men and knock them out. Oconee prepares to shoot Jim but discovers that he's out of bullets, while Aimee arrives to hold Artie at gunpoint and keep him from interfering. He manages to disarm her, while Jim and Oconee struggle. Jim manages to knock the knife-wielding Oconee to the ground and the half-breed falls on his own knife, dying. Aimee slips away but Jim figures that they'll find her eventually and heads back to the fort with Artie.
Later, Jim and Artie are at the Wanderer entertaining their dates, Lucy and Jeanne. As they explain how they saved the day that that Baldwin didn't know he was being used, the whistle alarm goes off. The agents get the women into the back just as President Grant comes in with his aides. He thanks them for their help, but notices the four champagne glasses on the table and realizes that they have company. He reads them Baldwin's resignation letter, saying that he's going to retire to spend time with his family after realizing that Rath was a traitor. Grant is relieved to grant his request, calls out to wish the ladies a good night, and departs. Once they're alone, Lucy and Jeanne come out, impressed that their dates are close to the President, and Jim and Artie tell them that their boss decided to let the ladies reward them.