In Philadelphia, two grad students are arguing Vulcans vs. Klingons as they go into a diner. A man walks out of the diner and locks the doors from the outside, while inside, the patrons and staff see an alien creature advance on them. Everyone panics and tries to get out without success, and then attack the creature. When the police arrive, they discover that the customers have beat another customer, Joe, to the point of death without realizing it.
After Claudia disappears, Artie goes through her room and remembers Brother Adrian’s warning about his creating an evil that will last the rest of his days. Leena comes in and assures Artie that they’ll find Claudia. When he goes downstairs, Pete and Myka asks what they’re going to do and he tells them that he’s sending them to Philadelphia while he looks for Claudia. He shows them the pocket-ping device that Claudia made for him and tells them about the riot, and sends them out. Once they leave, Brother Adrian arrives at the patio door and Artie recognizes him. Adrian is puzzled but introduces him and explains that he’s with the Vatican and needs Artie to help him recover Magellan’s Astrolabe. He knows that someone has used it to rewind time 24 hours, unleashing a great evil. Adrian needs the original user to use it again, undoing the first rewind. Artie suggests that the person using it may have been aware of the danger, but Adrian insists that the evil must be eradicated and goes on his way after giving Artie his card.
At the Regent Chatelet, Claudia watches a man at the hospital emerge and notices the eye tattoo on his wrist. As she checks her computers, she glances at the metronome artifact.
In Philadelphia, Pete and Myka interview the customers and staff and ask if they encountered anything weird like an old plate or a ladle. Pete gets a description of the creature they all saw and Myka figures that it’s something there that the cops didn’t come into contact with when they arrive. The agents decide to close down the diner so they can conduct a thorough search.
At a dental office in Philadelphia, a man comes in and the staff and patients see him as a giant tentacled monster. They attack him, knocking him out the window where he falls to his death. The man who locked the diner door the previous night is among those who gather to look at the body.
Claudia, wearing a good suit, goes into the hospital and “accidentally” drops some papers to distract a guard. She makes a scene until the guard lets her by without her security badge. Claudia then goes to the morgue and switches to a nurse’s uniform. The guard checks her badge, which is rigged to taser him unconscious, but the first security guard arrives. When Claudia prepares to use a Tesla on him, Artie arrives and hauls her out.
Pete and Myka go to the dentist’s office but don’t find any common denominator between anyone there, or anyone there and anyone at the diner. As they go over the drawings of the second creature, Myka gets nervous and admits that she’s scared of octopuses. She calls Leena to have her check police scanners and see if they can pick up a lead.
Claudia tells Artie that she plans to bring Steve back no matter what, and he warns her that they don’t get to use artifacts for their own selfish needs. She insists that it’s about Steve but Artie asks if she can’t bear losing him, and wonders if Steve would want her to risk everything. Claudia asks if he would use an artifact to rectify a mistake, but Artie angrily says that he won’t let her be seduced. Jane Lattimer arrives and Artie assures her that Claudia didn’t use an artifact and the Regents don’t need to get involved. However, they’re both surprised when Jane tells them that it’s okay for her to use the metronome to bring Steve back. Artie warns against it, worried that something could be released, but Jane insists. After Artie leaves, she asks Claudia is she’s sure. When Claudia says that she is, Jane says that they have to make arrangements.
A woman, Robin, arrives at home when the man from the two crime scenes comes up and says she lost her key. She touches it briefly and says it isn’t hers, and he takes the key and leaves. The woman goes inside and her husband Jimmy hallucinates seeing her as a monster.
Leena gets word of the incident and calls Pete and Myka. The husband has locked her up in the closet and called 911, but the police aren’t in a hurry to get there. The agents arrive and identify themselves, and disarm Jimmy, who has a shotgun. When Pete opens the closet door, Jimmy goes berserk and they disarm him and then release Robin.
Claudia and Jane return to Leena’s and go to the room where Steve’s corpse is resting. Jane assures Claudia that Steve will be entirely normal, but says that she needs to be there with her to make sure she doesn’t lose her way. Claudia places one hand on the ticking metronome and the other on Steve’s heart. Crying, Claudia concentrates and tries to bring her friend back, but nothing happens at first.
Artie arranges a meeting with Adrian at the local diner and asks him more about the evil. The brother says that the evil is unique to the user, and will cut through his heart like a dagger.
Claudia concentrates but nothing happens, and Jane tells her to have patience. He finally draws in a breath and Claudia starts with fright. Jane tells her to focus before she dies as well.
Artie says that he hasn’t been able to find anything about the evil and asks if it could be triggered by a resurrection. Brother Adrian admits that it is possible.
Claudia starts to die as well and describes seeing a white field and Steve standing there, facing away from her. Jane tells Claudia that Steve has to come to her and tells her to concentrate and breathe. Claudia finally gets Steve’s attention and he turns to face her, and in the real world Steve begins breathing and then looks up as Claudia hugs him.
Artie asks if Adrian can tell him more, even though Adrian says that knowing the evil won’t help him find the astrolabe. Brother Adrian explains that Robespierre used the astrolabe and unleashed the French reign of terror, and assures Artie that the only way to stop the evil is to undo the temporal rewind.
In Philadelphia, Pete and Myka claim that Jimmy got some bad mushrooms and hallucinated. They talk to the Robin, who describes the man who handed her the silver key. Peter realizes that the creatures are all tied into Cthulhu, a monster created by H.P. Lovecraft. They check with Leena, who confirms that Lovecraft suffered from waking dreams that he blamed on a silver key, the Key to the Gate of Dreams. The agents realize that the victims are the ones who are being targeted, not the persons making the hallucinations. They go to the house of the first victim to try and find a connection, and Pete discovers that they all went to the Philadelphia vs. Cincinnati game. Myka remembers that Theresa Hicks died at that game in a riot afterward.
At Leena’s, Claudia tells Steve what happened and assures him that he was a hero. She avoids telling him that he was dead and assures him that he helped finish Sykes and Marcus for good. Steve wonders why they’re not in his room and realizes that she’s hiding something because he can still sense lies. As he hears the metronome ticking, Steve realizes that he was brought back from the dead. He runs out as Claudia tries to explain.
The agents go to the stadium and review the video of the riot. They spot the three victims and realize that they all ignored Theresa. Ron Hadsell was her fiancé and couldn’t save her, and the agents realize that Ron decided that they were all monsters and used them the key. They check the footage and find a man who blocked the ambulance that took Theresa to the hospital, and Myka goes to find Ron before he can claim another victim.
Steve is seated out on the patio when Claudia comes out. She points out that people sometimes experience clinical death, but admits he was dead for 4,320 minutes. Claudia refuses to apologize for bringing him back and admits that it was selfish of her, but tells Steve that she’d do it all again. She hopes that he’ll forgive her but is willing to live with it if he doesn’t. As Claudia starts to walk away, Steve admit that he doesn’t know if he feels or what he feels, and tells her that it will take some time to get used to his new circumstances.
Myka goes to Ron’s apartment but gets no answer when she knocks at the door. She breaks in and finds photos of Ron and Theresa together, and a studio filled with models of Lovecraftian creatures. Meanwhile, Pete goes to find the driver, Jeff Green. Myka calls to tell her partner that Ron is definitely the guy but admits that Ron isn’t there. Ron arrives at Jeff’s house and runs when he realizes that Pete is after him. Pete chases him into a health center and finally tackles him, but Ron manages to touch the key to Pete. Ron says that there’s nothing they can do for him if they can’t bring back Theresa, and then yells to the people in the area. They all see Pete as a monster. Pete calls Myka but his voice transforms and she can’t understand him.
The health center members come over and try to attack Pete. Myka shows up just in time and holds them off, insisting that Pete won’t hurt them even though she sees him as a monster as well. Ron continues to try and provoke the crowd and Myka gives the gun to Pete and chases after Ron. The club members attack Pete, knocking the Tesla out of his hand, while Myka tackles Ron and manages to neutralize the key just in time. The health club members see Pete for who he really is and stop their attack.
As the police take Ron away, he says that he went to the police but they said that it was an accident. He admits that he couldn’t just shoot his victims so he heard about the key from a horror convention, hunted it down, and used it as the perfect weapon to show his victims who they really were. As they take him away, Pete admits that he doesn’t think Ron is any better than his victims. Myka agrees but says that she can understand how grief can drive people to do things they know they shouldn’t do.
Later, Claudia returns to the warehouse and finds Adwin waiting for him. Jane comes in and Claudia realizes that Jane didn’t get permission from the other Regents. When Jane insists that they had a right to do it, Adwin warns that there are consequences. Steve may be alive but he’s not a free man as long as he’s linked to the metronome... and the warehouse and the Regents as well. Since they don’t know the downside of the artifact, they’ll keep the metronome and put Steve under lifetime supervision. Adwin warns that if there is a downside then the Regents will take action to eliminate him and protect the world.
When Pete and Myka return to Leena’s B&B, they’re surprised and happy to discover that Steve is alive. Claudia arrives and Artie realizes what happened when Adwin arrives. He assures Claudia that they’re okay and lets her go. However, as she joins the others, Artie gets a ping registering the presence of an artifact: the dagger that he saw in his dream of Claudia killing him. He tells the others that it’s nothing and joins them, but Pete gets a bad vibe from what’s happening.