In the Peruvian Andes in 1540, the local tribe holds a ritual ceremony. The high priest, Manco, gives a warrior a sacred golden headdress and tells him that he is the holder of the key and will protect the Garden of Gold forever.
In the present day, MacGyver goes to the University of San Marcos in the city of Lima, Peru. He meets with Maria and wonders how she's going to find the treasure that her father, a famous archaeologist, couldn't. MacGyver warns that her father died in the Peruvian mountains after searching for 15 years but Maria insists that her people are starving and the treasure of Manco could be used to stabilize the government. She insists that the myth of the treasure is real despite MacGyver's doubt, and says that their school friend Enrique murdered her father for his journal so he could find the treasure and finance his revolution. She explains that her father lead an expedition to a conquistadors' camp and found a golden headdress. The leader, Manco, gave the headdress to a warrior appointed as a guardian, and her father believed the headdress is the key to finding the treasure of Manco. MacGyver agrees to help her and Maria proposes they go to where her father and his guide were murdered.
MacGyver and Maria drive to the mountain base camp of the Peruvian National Army. Captain Diaz commands the military post and found the body. Ramon, the son of her father's guide, comes up and explains he'll be acting as their guide. He vows to take revenge on Enrique if he finds them but Maria and MacGyver insists that it's not about revenge. The best he will do is promise he won't involve them in his personal interests. They meet with Diaz, who claims that Enrique's guerrillas killed Maria's father and guide. He wishes them well and offers them a tent for the night.
That night, Maria explains her father's theory about the headpiece and symbols that represent the "Steps to the Condor." MacGyver notices two cats and Maria talks about how she translated a phrase referring to "Manco's Place of Infinite Vision." Guerrillas suddenly cut through the side of the tent and take them away at gunpoint to their rebel camp. They are taken to Enrique, who tells the guerrillas to untie them. He wonders why they're there and Maria slaps him. Enrique knows that the military has blamed him for her death but insists that he didn't kill her. MacGyver wonders why he's changed to violence since their school years, and Enrique says that the government is corrupt and can't be fought from within. Maria doesn't believe him, even after he explains that the guerrillas abducted them because they suspected they were CIA agents or drug dealers. Realizing he can't change their minds, he tells them they're free to go back to the military base.
The next morning, MacGyver, Maria, and Ramon prepare to depart and Diaz warns that the guerrillas are dangerous. He assures them that his patrols will find the guerrillas eventually and deal with them. Once he leaves, Ramon says that he would have killed Enrique on the spot and MacGyver tells him that he needs to get control, and that's there's no satisfaction in violence and vigilante justice. They ride into the mountains to the spot where Maria's father was killed, a wide-open area with no shelter. The area has a view of the mountains and MacGyver figures it's the Place of Infinite Vision. He studies the lines between the two cats and figures they represent two mountains. Comparing the headpiece to the horizon, he finds two peaks that match the pattern. Ramon directs them to an Incan ruin that lies along the path. Suddenly a gunshot goes off and they duck into the bushes, dropping the headpiece. Men wearing guerrilla uniforms ride up, take the headpiece, and leave. Ramon vows vengeance and prepares to follow the guerrillas, but MacGyver warns he's likely to get himself killed. He insists they get the headpiece back his way.
At the military base, Diaz gets word that one of his patrols hasn't returned yet. He orders his men to get ready to move out.
MacGyver and the others proceed on foot, following the hoof prints. They come to a camp and see the guerrilla give the headpiece to Enrique. While MacGyver and Maria watch, Ramon goes back to the horses and then circles around to shoot Enrique. MacGyver discovers that Ramon has slipped and goes to stop him. He arrives too late but Ramon only wounds Enrique. The guerrillas ride up after him and quickly surround Ramon and the others before they can escape. They are taken to the camp where Ramon takes sole credit for shooting Enrique. Enrique still continues to insist that he didn't kill their fathers. He takes them to the guerrillas that took headpiece, tied up as prisoners. Enrique explains that his men captured the fake guerrillas, who are wearing dog tags and are members of Diaz's death squad. MacGyver apologizes for doubting his old friend.
Diaz and his lieutenant try to find the missing death squad, and the captain studies the stolen journal. They realize the guerrillas were heading for the nearby Incan ruin and head in that direction.
MacGyver and the others find a lid with the same symbols on the headpiece. Beneath is a long vertical shaft with no steps down like those shown on the headpiece. Enrique realizes the headpiece indicates a nearby cliffside. They investigate and find steps leading down.
Diaz and his men secretly approach the rebel camp and spot their captive men. They also spot MacGyver and the others taking the stairs downward and go after them. Meanwhile, MacGyver finds a stone tablet imbedded in the rock with a picture of a condor. It's hollow and they find a tunnel beyond. Following it, they find Manco's Garden of Gold and a long-dead corpse skewered by a spear. Maria finds a bag containing a record-keeping rope and a handful of unknown seeds. They find a symbol of a goddess with a slot for a mouth and MacGyver realizes the headpiece functions as a key. The panel opens to reveal a larger chamber and a giant statue of a god holding dishes in each hand. Large urns are on either side. However, Diaz and his men enter and he congratulates them for finding the treasure.
Diaz opens the urns but discovers they contain nothing but seeds. MacGyver explains that the statue is of the god Quintano, protector of the fields. The natives brought the seeds to Quintano when the conquistadors burned their fields. The Incans through the seeds down the shaft and MacGyver figures the priests had a way to get the seeds out. MacGyver offers to find it if Diaz releases the others, but the captain refuse to negotiate. MacGyver examines the statue of the god and mimics its position, and then pushes down on one of the arms holding a dish. Placing his full weight on it, MacGyver forces it down, partially opening the statue's mouth. Diaz has Enrique stand on the other arm and they put their full weight on it. The mouth opens and tons of seeds pour out, burying Diaz. Enrique and MacGyver jump the soldiers, knocking them out. Diaz goes for his gun and Ramon knocks him out. MacGyver points out that the headpiece showed grain and he realized that it indicated the entire facility was a giant silo. "Quintano" was MacGyver and Enrique's old ski coach who almost got them killed.
Later, Enrique promises to turn Diaz and his men over to the government once they agree to a public trial. Ramon and Maria will testify, assuring a conviction. Enrique agrees to try a more peaceful approach to defeating the government, and plans to use the potentially extinct seeds to feed the people of Peru.