Martha Jones is in the Hub lab preparing to do the autopsy on Owen while the rest of the team looks on. Jack arrives and tells everyone to stop until he gets back. He drives to a club and meets with a young girl, who is waiting for him. He asks her where "it" is and she warns that if she finds it, he'll owe her a favor. She uses Tarot cards to reveal that the people who found it and realized what it could do built a church on top of it. As Jack goes, the girl asks what he would do if she told him not to use it. Jack wonders why she doesn't know the answer. Once he's left, the girl admits that she does know the answer... and draws the Death card.
Jack goes to the church and starts his search. He discovers that there are Weevils sleeping inside. He makes his way past them to a wooden case that is part of a shrine of junk the Weevils have built. Searching further, Jack finds another case but inadvertently hits the keys on the pipe organ it's resting on, waking the Weevils.
Later, Jack returns to the Hub with the box and opens it to reveal a resurrection glove. Gwen warns that they can't use it after what happened with Suzie, but Jack insists he's going to bring Owen back. He refuses to discuss the matter and insists it's a different glove and will work for him. He warns they only have two minutes and tells them to prepare whatever it was they want to say for Owen before he's gone for good. Jack dons the glove and touches Owen's corpse, calling out to him. Nothing happens at first but then Owen suddenly screams as he wakes up. Jack warns him he doesn't have long and Tosh tells him that she's always loved her. Jack asks him for the code for the alien morgue. He then tells Owen to be brave as he faces the darkness, and Owen dies again. But he revives despite the fact that Jack isn't using the glove. Owen wonders if he was meant to stay alive but then looks at his chest wound in horror.
Owen grabs his medical equipment and tries to investigate his own condition, but Jones notes that he might be a bit biased. They wonder where Owen is getting the energy to survive. The last time, the revived person got their energy from the glove user, but they can't detect any energy exchange between Jack and Owen. They admit they have no idea where the gloves came from. Jack orders Tosh to analyze the glove and puts Owen under quarantine.
Gwen calls Rhys at home and wakes him up. She breaks into tears and admits it's been a tough day.
Martha comes to see Owen and attach a monitor to check his energy levels. She asks what it was like when he died but Owen wonders if he should tell her. She insists and he describes the experience of rushing toward the light and arriving at the Pearly Gates. Martha realizes that he's joking and Owen admits that he doesn't remember anything. He tells Martha about what Suzie said, that there was something moving in the darkness. Suddenly Owen blacks out and finds himself in a void surrounding by whispering voices. He comes back to reality as Martha calls Jack in. He tells them that he experienced what Suzie described, something that was waiting for him.
After finishing her analysis, Martha warns that Owen is transforming into something else, but they still don't know where the energy is coming form. Jack gets Owen to describe what he experienced but Owen admits he doesn't know. After the meeting, Tosh insists she meant what she said. However, Owen figures she just said it out of grief and refuses to hear her say anything else. As he goes off on his own, he finds himself back in the void as a voice chants unknown words. Owen finds himself back in the same world, his eyes solid black. He chants the same words and then snaps back to normal. In the lab, Martha registers the energy readings and warns jack they've gone off the scale. They go to find Owen and discover he's left. Jack insists that Owen is harmless but Martha isn't convinced, and warns they need to stop thinking of him as Owen.
Owen goes to a bar and drinks, and a woman comes over to flirt with him. He kisses her and she grabs at his crotch, but he has no blood and doesn't react. Jack arrives, following the monitor bracelet, and Owen snaps at him. He throws a punch and Jack and the bouncers kick them both out. The police arrive and Jack let them arrest him. As they're taken is taken away, the Weevils watch from the shadows.
Owen is locked in a cell and Jack tells him to calm down before he permanently injures himself. Owen realizes that he can no longer metabolize alcohol and stands on his head so he can vomit it up. Owen realize that all of his biological functions have shut down and envies Jack, who notes that immortality is overrated. Owen wonders if Jack brought him back out of guilt, and Jack explains that he was hoping for a miracle, and still is. He finally says it's time to go back to the Hub.
At the Hub, Tosh has been checking Owen on the CCTV and finds the footage where his eyes turned black and he chanted.
As Owen and Jack go to their SUV, the Weevils emerge from the shadows. Jack figures that they're after him for stealing the glove. They run and the Weevils pursue them into a parking garage. Jack goes to find an exit but dozens more Weevils find and chase him. The two men run to the rooftop and the Weevils surround them and then bow down. Owen's eyes turn black and he starts chanting again.
At the Hub, the team uses a translation device on Owen's words and determine he's saying "I shall walk the Earth, and my hunger will know no bonds." jack and Owen return and go to the cells. The Weevil there bows before Owen, who realizes that he's either their king or messiah and neither one is good. Gwen has a report indicating that it's happened before during the period of the Black Death. According to legend, the person who says the words is Death himself. According to the records, 15th century villagers built a wall around the town to protect them from the Black Death. A young girl died and a priest brought her back by performing a miracle, but she brought Death back with her. The church is St. Mary's, where Jack found the glove, and they realize the village eventually became Cardiff. According to the legend, Death needed 13 souls to get a permanent hold on the world. The only thing that the records say can stop Death is "faith". Owen realizes that Death is trying to get into reality through Owen. The readings are at 80% and rising, and the team wonders what they can do when Owen is already dead. Owen suggests they embalm him to freeze his neural pathways and make sure.
Jack and Martha prepare the embalming process while Gwen asks Owen if he's sure. Owen insists that he can't do anything that the living do and he's ready. He goes to the lab as the energy levels reach 95%. They strap him down and start to give him the first injection, The glove suddenly comes to life and attacks Martha. Jack pulls it free and orders lockdown. They try to find it beneath the cabinets and it goes after Martha gain. Jack pries it off and throws it onto a table while Owen tries to free himself. He gets free, pins the gun down, and shoots it, destroying it once and for all. They turn to Martha and discover that she's been aged decades in a matter of seconds due to the glove. The energy readings on Owen reach 100% and Death speaks through him, saying its hunger will know no bounds. Black mist spews from Owen and explodes outward.
The team takes Martha to the hospital and they realize Death is out there somewhere. The doctor warns that Martha has suffered considerable strain to the heart and she could die at any time. Jack promises Martha that they'll find a way to reverse the process. Gwen tries to figure out what's going on and Jack tells Owen he needs to go back to the Hub, but Owen insists that it's "duroc," translating as "hunger," and that he's free of its influence. Jack looks outside and sees that the Weevils are lurking outside, and figures that Death would come to a hospital.
The black mists goes to the ICU and starts killing the patients one at a time, manifesting as a skeleton.
Torchwood begins evacuating the hospital as the alarms go off. They start in the children's ward but one boy, Jamie, is in the bathroom and doesn't hear the alarms. Ianto determines the alarms are coming from the ICU ward. Meanwhile, a nurse realizes that Jamie is missing and goes to look for him. She hears the voices whisper "duroc" and looks under Jamie's bed. Death appears behind her.
Jack and Gwen go the ICU and confirm there have been seven fatalities. There's been one more, making eight, and Jack realizes that there are five of them. They realize the creature is on the eighth floor and Tosh and Owen go there. He can sense the creature and pursues it.
Jamie tries to locate someone else and finds the nurse, drained of her life force. He ruins down the hallway but a locked doorway blocks his path. The black mist pours down the hallway but Owen comes in through a side corridor and gets Jamie out.
Gwen confirms there are now 12 dead, and that Death will become unstoppable when it obtains the 13th soul.
Owen and Tosh try to get Jamie out but the doors seal itself. Jamie explains that he's there for chemo for his leukemia and the first treatment failed. Ianto discovers that the priest managed to stop death at 12, and that somehow the girl that died, Faith, stopped Death. Owen realizes that the girl had nothing to lose because she was already dead. Owen, overhearing, tells Jamie that the ones who can beat leukemia are the ones who are convinced they can beat death. He tells Jamie to watch him beat death. Tosh gets the door open and Owen sends Jamie on. Tosh insists that she won't let Owen face it alone, but he kisses her and then locks her out using her remote device. Death arrives and Owen demands to know how long it can last with only 12 victims. He confronts it and it attacks him. The two of them struggle and Owen demands to know what else it can do to the dead. Jack and Gwen arrive but can only watch as he dares the creature to finish him. It finally dissipates and Owen realizes that he still exists. Martha has her youth restored upon the creature's death.
Later, Owen apologizes to Martha for getting her hurt. She warns him that he soaked up a colossal amount of energy but it's slowly dissipating. She has no idea how long it will take for the energy to fade. Owen tells Jack that the tow of them are responsible for the 12 deaths and that as a doctor, he wants to go to work and even the score. Jack tells him that they'll see. Tosh asks Jack what they do now and he doesn't have an answer.