A man is walking along the road at night near Great Falls, MT. A driver is drinking heavily and come down the road, passes out, and hits the pedestrian. The driver runs to the man, who is clearly dead, and then gets back into his truck and drives away.
The next morning, an eagle is picking at the corpse when a state trooper, Jack Spradlin, spots the body and pulls over to investigate. The officer checks for a pulse, finds nothing, and goes back to make his report. Meanwhile, the dead man's wounds heal and he gets up and walks away.
At the Letters headquarters, Sam is taking a drink of water and discovers that he's still bleeding from the mouth. He quickly washes it down the sink as Dean comes in to ask if he's heard anything about Kevin. Sam admits that he hasn't and Dean figures that they need a lead before they start climbing the walls. His brother shows him an article about a zombie sighting in Great Falls.
The brothers drive to Great Falls, posing as FBI agents, and talk to Jack. He confirms that the body he examined was dead and figures that it's a zombie. The dispatcher gets a report about a corpse that turned up in nearby Livingston, mauled by a grizzly, and Jack confirms that it was the corpse that he saw. He prepares to leave but Sam and Dean tell him to stay put while they check it out.
When the brothers arrive at the Livingston morgue, the coroner explains that there was no ID and the fingerprints weren't on file. He explains that a bird got at the liver and ate it. As the brothers go outside to discuss the case, the dead man wakes up, his wounds healed. The brothers spot him, grab him, and drag him into a storage room. The man says that his name is Shane and that all he can remember is that he keeps dying and coming back to life. He asks them to shoot him and make sure that he stays dead, and Dean reluctantly lets up on him and says that he's coming with them.
Back at the motel, the Winchesters check Shane's blood and have him drink holy water. Shane passes the tests and he says that he's been dying as long as he can remember. He can only remember back a few years, and people only call him Shane because he needs some kind of name. Shane first remembers dying when he was killed in an avalanche in Europe. He realized couldn't be around other people who might realize what he can do so he moved into an isolated cabin. A couple of nervous pot growers shot him and Shane moved on, only to be hit by the truck. Dean lets him go to the bathroom to clean up and Sam suggests that a witch might have cursed Shane. He proposes that they get another room and let Shane stay there while they work things out.
That night, Shane is sleeping when a woman enters the room and sits down on the bed next to him. She strokes his face and Shane grabs her hand and asks who she is. The woman realizes that he doesn't remember and then draws a knife. Shane throws her off the bed and she comes back at him as Dean comes in. He tries to stab the woman but she easily trips him and then knocks Sam back with a telekinetic blast. Shane finally gets the upper hand, displaying some martial arts skill, holds the knife to her face, and asks who she is. The woman says that now she's his worst enemy, grabs the knife, and fades away. Shane explains how the woman reacted to him and then collapses to his knees, clutching at his chest.
The next morning, Sam and Dean sit and watch Shane's body and try to work out what to do next. There's a knock at the door and Dean peers through the curtain to see a woman and her child outside. She explains that she's looking for a missing corpse and the coroner said that they were at the morgue. When they wonder what why she's interested, Hayley introduces her son Oliver and says that Shane is the boy's father. She sees Shane's corpse inside the bed, tells Oliver to stay with Sam and Dean, and goes to Shane.
Later, Hayley tells the Winchesters that she went mountain-climbing with friends in Europe. She's surprised to learn that Shane told them about the avalanche, and explains that once he came back to life, he helped her down to the bottom. They fell in love, spent the night together, and Shane had a heart attack. He came back to life later and Hayley ran away in terror. She eventually hired private investigators to locate Shane but they failed, and she gave up until a couple of months ago. Before Hayley can explain further, Shane comes out and Hayley calls Oliver over to meet his father.
Sam goes back inside and does some research. He tells Dean that they're dealing with Prometheus, the Titan of Greek Mythology that gave birth to Zeus and the gods of Olympus. When Prometheus stole fire to give to Man, Zeus imprisoned him and made him die every day and then come back. Sam figures that the woman was Artemis, Zeus' daughter and armed with a dagger that can kill gods.
Sam and Dean call Shane inside and try to tell him that he's Prometheus. He doesn't remember but figures that he should get away from his family to keep them safe. Sam says that they'll help him but they will take him somewhere safe. Before they can come up with a plan, Hayley brings an unconscious Oliver in and explains that he fell. Sam figures that Oliver has the same curse that realizes that he's dying and Hayley wonders what he means.
The Winchesters take Prometheus, Hayley, and Oliver to Letters headquarters. Dean wonders why Prometheus' curse is on Oliver, and Hayley explains that Oliver first started dying when he turned 7. Sam explains that the age of seven marks one of the first Greek rites of manhood, and suggests that it's genetic. Hayley apologizes to Prometheus for running out on him and asks for an explanation. They tell her who Shane really is and who they are, and she wonders how they deal with the problem. Dean says that normally they summon the person responsible, beat him up until he drops the curse, and takes him out if that fails. Hayley points out that they're going up against Zeus, and goes to check on Oliver when he comes back to life. Dean tells Prometheus that he and Sam are going to go after Zeus with or without him, and Prometheus agrees to help them.
The brothers and Prometheus go through the research books. As Hayley comes back in, Dean finds a reference to a Greek hunter, Drakopoulos, who fought Zeus. The Men of Letters translated his journal, which describes how the hunter lured Zeus into a trap made from a tree struck by lightning. To perform the summoning, they need frozen lighting--fulgurite--and the bone of a worshipper of Zeus. As they start to do an Internet search for the ingredients, Hayley points out that the journal ends at that point and they have no idea if Drakopoulos succeeded or not. Dean says that it's the best chance that they've got, and Sam finds an obituary for two Greek patrons. Sam and Prometheus head off to rob the graves, while Hayley tells Dean that New Age types make cheap jewelry out of fulgurite.
As Sam and Prometheus dig up the grave, Prometheus asks Sam why he's doing it. Sam points out that Prometheus saved Mankind by stealing fire for them, but Prometheus says that none of it means anything if he can't save his son.
Dean and Hayley drive to a jewelry shop with a sleeping Oliver in the back. When Dean tries to reassure Hayley, she points out that she's going to ask Zeus for help. Dean warns her that Zeus is no one's friend and they'll have to get him to do what's right.
Once they have the ingredients, the group returns to the Letters headquarters beneath the dam. Dean and Sam cast the summoning spell. The lights flicker and Zeus materializes within the containment circle. Dean suggests that he just help Oliver and they all go home, but Zeus tells Prometheus that he's been looking for him. Prometheus tells him to break the curse and Zeus realize that it's his child who has the curse. When Dean asks if they'll do it the easy way or the hard way, Zeus tells him to break the trap so he can cure the boy. Dean refuses and Zeus points out that if they leave him there then Oliver will suffer.
After a moment, Dean says that they're leaving and walks away. Zeus turns to Oliver and says that the boy needs him, and she runs over and breaks the circle before Dean can stop her. Zeus steps out of the circle, chuckling, and blasts the others back with lightning. Zeus asks Hayley to bring Oliver to him, and she hesitantly brings the boy over. Dean and Sam try to sneak up on Zeus, but Artemis arrives and pins them to a pillar.
Zeus admits that he couldn't conceivable of a worst fate for a beautiful child, and asks if Prometheus has experienced Oliver's death yet. He asks Hayley if Prometheus suffered to see his son die, and then slams Prometheus to the floor and says that a thousand children would have to suffer for the Titan to understand his pain. Zeus chokes Hayley and then tells Oliver that he has a special job for him. He calls Artemis over and she tells Sam and Dean to move. As Artemis leads them away, Sam tells Dean that Artemis is the Goddess of Hunters, but says that she's not worthy of worship anymore. Artemis slams them into the wall and says that she's still worthy.
Back in the main chamber, Zeus rams a hand into Prometheus' chest. As he screams in pain, Hayley and Oliver watch in horror.
Sam reminds Artemis that it took her seven years to hunt Prometheus down. He suggests that she didn't want to find Prometheus and claims that the Titan told them that he's in love with Artemis.
Zeus continues to beat Prometheus, warning that he's just getting started. As Prometheus screams, Artemis hears him and Sam says that Prometheus told him that she let Prometheus go free before so they could have a tryst. He figures that when Artemis saw the zombie article, she knew that Zeus would find Prometheus so she had to come hunting for her lover.
Zeus turns to Oliver and says that he should enjoy being an immortal and get used to dying. He prepares to kill him... and Artemis comes in with a bow and says that it's time he stops. Zeus insists that he's doing it for their own kind, to get revenge on Prometheus for preventing them from ruling the world. Undeterred, Artemis tells her father to let them all go. He commands her to obey him and Artemis says that she's not the father she once knew. When she fires the arrow, Zeus picks up Prometheus and uses him as a shield. He promises Prometheus that Oliver will go on the mountain, and Prometheus grabs the arrow and pushes it through his chest and out his back into Zeus. Artemis runs to Prometheus and pulls out the arrow, and then looks up at Hayley. After a moment, Zeus and Artemis both fade away.
Later, the Winchesters make a funeral pyre for Prometheus, letting the flames he gave to humanity consume him. Hayley watches and says that she's sorry, and Dean gives her a comforting hug. Sam goes to Oliver and suggests that they go get ice cream sundae. Oliver quietly says that he wants to stay.
As the Winchesters drive off, Sam says that he got lucky guessing that Artemis and Prometheus were romantically involved. He admits that he was being naïve when he thought he'd come out of the trials unscathed. Dean assures him that he's not going to die like Prometheus, but Sam points out none of the people they know chose death. His brother doesn't buy it and promises to make sure that Sam dies of something normal.
When they get back to the motel, Dean goes to his bed and prays to Castiel. He asks the angel to watch over Sam but gets no response, and wonders where his friend is.