MacGyver is returning home through the Little Haiti neighborhood after a hockey game. In a nearby shop, Sergeant Concassuer is threatening the owner, Denise, who has signs up protesting the dictatorship in Haiti. He reminds her what day it is and Denise starts to pay up, but her niece Cherine protests and tells him to get out or he'll call the police. MacGyver comes in and Concassuer leaves. He warns Cherine that he'll introduce her to Baron Samedi the next time they meet. Denise greets them and Cherine leaves for a protest rally. Concassuer and his men grab Cherine outside and MacGyver runs out and is nearly run over. As they go, Concassuer drops a voudon doll in the street. Denise quickly picks it up.
Later, Sergeant Rudley takes Denise's statement but she claims she didn't see anything useful. MacGyver gives his statement and insists that Denise can identify Concassuer. Rudley warns that it's the third recent kidnapping but nobody will testify. After Rudley leaves, MacGyver asks Denise why and she claims he wouldn't understand. She finally explains that the Tonton Macoute, Papa Doc's former secret police in Haiti, are responsible and left the voudon doll as a warning.
MacGyver goes to see Mama Lorraine, who is curing a client's headache. He shows her the voudon doll and she explains that it's sacrilege. She devotes herself to the left and right hand, good and evil, but some dedicate themselves only to evil. The Tonton Macoute have placed a curse on Cherine. Lorraine refers MacGyver to Dr. Pierre Redemteur, who knows Cherine. He explains that Cherine has been protesting the Haitian government and explains that the Tonton Macoute stay to the shadows. When MacGyver mentions that Concassuer described Baron Samedi, Redemteur explains that Samedi is the keeper of the graveyard and master of zombies. The doctor explains that the proper drug can induce a coma state that can't be distinguished from death. Some of his own students at the college are joining the religion.
Concassuer takes Cherine to see Colonel Devraux, one of Papa Doc's men. She accuses him of using voudon for his own purposes but Devraux insists he'll bring peace and stability to their people. He blows a powder into her face and she collapses, seemingly dead.
Back at Mama Lorraine's shop, MacGyver cuts open the voudon doll and determines the oily silt inside came from a dried riverbed. He realizes the oil comes from a turbine at the old Liberty Dam. They go there and spot Concassuer leading a religious ceremony. Cherine is there, lying in a coffin. MacGyver refuses to believe that there is magic but Mama Lorraine insists that it's a drug that will leave Cherine conscious but totally paralyzed. Mama Lorraine has an antidote but warns Cherine will only have a few hours at most before she truly dies. Mama Lorraine joins the procession and distracts the guard, MacGyver slips in and meets Mama Lorraine when she comes after him. He goes to look for Cherine while Mama Lorraine joins the ceremony. Concassuer greets her and they watch as Devraux, dressed as Baron Samedi's representative, makes his entrance. He rallies the people to conquer the enemies of Papa Doc and displays Cherine. He offers to bring her back as his servant.
Once the curtains are closed, MacGyver slips backstage and tries to revive Cherine. Outside, Concassuer tries to convince Mama Lorraine to join her power with them but she refuses. He warns her to carefully consider his offer. She leaves and finds MacGyver, but Devraux and Concassuer find them. They grab MacGyver and beat him, and then Devraux blows more of his dust into MacGyver's face. As he collapses, Mama Lorraine tries to help her but Devraux warns that MacGyver will soon pass out unless Mama Lorraine joins forces with him. In return he'll let her revive MacGyver. She says she'll do what she must do, and slips MacGyver a bit of a herb to preserve him a little longer.
They take Mama Lorraine to Devraux's chamber and place MacGyver in a coffin and take him ot to a van to be taken away. Once alone, MacGyver eats the plant as the coffin is hauled away. He pulls a rope through a knothole in the side of the coffin, and lets the back and forth motion of the van shift the coffin until the side is pulled off. MacGyver then pounds on the back of the cab and knocks out the two men when they come to investigate. He drives away in the van and heads back to Mama Lorraine's shop. He staggers inside and takes some of her plants as a temporary cure. He hears someone come inside: Dr. Redemteur. The doctor explains he was sent to recover the voudon doll and draws a gun on MacGyver.
Redemteur explains that he's and Devraux are working together and he used his position to recruit students and provide the proper poisons to the colonel. He also warns MacGyver that he'll still need hospitalization. MacGyver keeps him talking long enough to grab some of Mama Lorraine's flash powder and distract Redemteur so he can knock the man out.
Concassuer tells Mama Lorraine to hurry. She warns him that the very air is poisonous and he nervously backs out.
MacGyver returns to the dam and drops the voudon doll behind the guard. When the man comes to investigate, MacGyver swings down and kicks him unconscious.
Mama Lorraine begins the ceremony to revive Cherine and demonstrate Devraux's power. Meanwhile, MacGyver enters the damn and finds some empty oil barrels and a circuit box with wiring. He uses the wiring to tie a brick to a gate and balances the oil drums atop the brick.
Mama Lorraine wakes up Cherine and Devraux prepares to make his entrance. MacGyver slips in through the back and crawls beneath the stage. He finds the trapdoor that Devraux uses to make his entrance and a wire leading to the catch. He also finds a remote activator. He then goes down to Devraux's dressing room and waits until the colonel starts up the ladder. MacGyver slams the ladder and Devraux into the wall, knocking the colonel out.
Concassuer realizes that Devraux is taking too long and starts to send a man to investigate. Suddenly MacGyver, dressed as Baron Samedi, appears in a flash of smoke and tells the worshippers gathered that Concassuer and the others have no magic and are their enemies. He uses the remote activator to set off another flash and flees with Mama Lorraine and Cherine. They flee down the tunnel, get through the gate, and then pulls the wire, releasing the oil barrels to fall down on Concassuer and his men as they follow.
Later, MacGyver is released from the hospital and Mama Lorraine tells him that Cherine will recover in time to testify against Devraux. MacGyver admits that he has a lot to learn about her religion and she explains that she interceded for the gods and he doesn't have to sacrifice a goat because he's a vegetarian.