In the bronze sector, Nick tells his uncle, Paracelsus, that Claudia is no threat. He then uses a pair of tech-glasses to bring Paracelsus up to speed on everything that has occurred since he was bronzed. Once he's acclimated, Paracelsus thanks Nick for freeing him, and his nephew asks him to make them mortal again. Paracelsus considers the unconscious Claudia and ponders what to do next.
When they return to the warehouse, Pete and Myka use the durational spectrometer to review what happened in the bronze sector. They witness Paracelsus slapping Nick but can't read lips to tell what they're saying. Myka checks the files and discovers that several artifacts are missing. Meanwhile, Artie and Steve put Claudia back in the bronzer and repair the damage. However, Artie discovers that the artifact that powers it, a bronze stele, has been stolen. Paracelsus has left a flaming message in the compartment, trigged by the light. It says "Sutton know what I want" and they realize that it's a ransom demand.
At the B&B, Abigail restrains Charlotte's shadow with the Folsom Ball & Chain and stands watch over her. The agents arrive and question Charlotte about Paracelsus' whereabouts. She's shocked that Nick didn't follow the plan and wait for her, and points out that Nick liked Claudia and didn't want to hurt her. Myka reminds them that Paracelsus slapped Nick, probably because the teenager didn't agree with his plan to bronze Claudia. Charlotte explains that her husband Bennett Sutton's brother is Paracelsus, an alchemist who used artifacts in his research.
In the 16th century, Paracelsus pays Sutton to participate in his experiment to use the Philosopher's soul and a copper Egyptian Bowl of Life to grant immortality. As Sutton discovers that his brother has drugged his wine, Paracelsus reveals that he has captured Nick and Charlotte to use as test subjects as well. The alchemist begins his experiment and exposes all three of his relatives to the fumes from the Philosopher's Stone.
Charlotte explains that agents from Warehouse 9 eventually captured Paracelsus and bronzed him. His experiment was successful and Charlotte was forced to watch as Nick fell in love again and again, only to watch his beloved die of old age. She planned to free Paracelsus so he would lift the curse of immortality from them, and assumed that he would cooperate. When they wonder where to find Paracelsus, Charlotte says that he will head for his laboratory in what is now Istanbul. However, she doesn't know exactly where his lab is. Only Sutton knows for sure since he went there voluntarily, and the team sets out to find him.
Eleven hours later, Artie is still holed up in his office running Internet searches. Pete tries to talk to Myka about her cancer, asking why she hasn't begun her cancer treatments. She snaps at him, insisting that it's a personal matter, and Pete warns her that people can't "handle" cancer. Artie finds Sutton and tells the agents that he's posing as a Russian businessman, Vladimir Kamenev. Sutton is engaged to a rich duchess living in Luxembourg and she is throwing a dinner party. Artie tells Pete and Myka to take Charlotte with them and convince Sutton to take them to Paracelsus' lab.
Steve calls Artie from the bronze sector and warns him that the bronzed Claudia is dissolving. Artie checks on it and realizes that Paracelsus used the stele to bronze her rather than the machinery it was mounted in. The artifact is unstable and eventually Claudia will dissolve. When Artie and Steve go back to the office, they check the computer for bronze-related artifacts that they can use. The computer slows down to a crawl just as Mrs. Frederic arrives. However, she appears extremely confused and distracted. They tell her what has happened and she says that she has to access the restricted files. Much to their surprise, she walks off rather than disappearing as mysteriously as she came.
In Luxembourg, Pete, Myka, and Charlotte arrive at the dinner party. Sutton is with the duchess as she announces that the two of them are getting married. Charlotte tells the agents that Sutton is simply marrying another woman so he can get access to her jewels and steal them. Sutton spots them and leaves with the duchess, and the trio goes after him.
Mrs. Frederic goes to the storage room in his office and uses an electronic key to reveal a hidden chamber within. She tells Artie to stay outside and then goes into check the files. However, the file she is looking for is redacted by the Regents. Meanwhile, Steve comes in and tells Artie that Claudia is still crumbling. Artie points out a stabilizing device that they can try and then checks the computer.
Sutton escorts the duchess to her bedchamber and proposes a toast. Once she collapses from the drugged champagne. Once he does, he starts to take her gems. However, the agents arrive and order him to halt. The duchess manages to call for her guards just as Charlotte arrives and shoots Sutton dead.
At the warehouse, Mrs. Frederic tells Artie about the redacted file on Paracelsus. She prepares to contact Kosan but then sits down as her confusion grows. Artie is unable to get her to focus and she wanders off.
The duchess runs to her beloved, but faints when he comes back to life. The duchess' guards run in and the team easily defeats them. Sutton slips out in the confusion and the agents have Charlotte stay with the duchess while they go after him.
Steve hooks up the device and talks to her inert statue about how he misses her talking all of the time. He's unable to get a reading just as Artie calls and says he has a plan to use a blood sample from one of Claudia's family members to boost her DNA and slow the disintegration. Artie tries to call Claudia's brother Joshua but gets a voice mail. As he leaves a message, Artie worries that he will have to do something desperate.
The agents chase Sutton through the manor dining room, fighting past the guards. Pete finally leaps on the main table, runs to the end, and tackles Sutton.
After checking on Mrs. Frederic, Kosan tells Artie that it doesn't look good. However, he's more concerned about the warehouse itself and takes Artie into the restricted area. The center of the area is the Eldunari, Warehouse 13's central nervous system and the link between the Caretaker and the warehouse. The patterns that make up the nervous system are coming unraveled and Kosan explains that the Mrs. Frederic's mind is falling apart in the same way.
Pete and Myka take Sutton back to the bedroom and the duchess, furious, slaps him. She storms off with her security guards and the agents tell Sutton what's happening. Sutton points out that Paracelsus developed the bronzing process in the first place, and blames Charlotte for freeing his brother. Disgusted, Sutton warns them that Paracelsus is insane and tells them what happened once he woke up after the experiment.
Sutton confronts Paracelsus, who stabs him in the chest to prove that he can't die. The alchemist explains that he "killed" each of them a dozen times while they slept to make sure that they were immortal. He admits that he had to kill an entire village for the components to make them immortal, but dismisses it as a small price to pay.
After he left his brother's lab, Sutton went to the authorities. The Warehouse 9 agents learned of the incident and came to arrest Paracelsus and bronze him. However, before they could get there, Sutton split the Philosopher's Stone in half and hid the two parts. He kept the crystal inside and made a ring from it, and uses it to make money by displaying its "magical" power to restore plants to life. Paracelsus took the ring when he escaped the bronze sector, but he doesn't have the two halves. Sutton warns the agents that Paracelsus will go to his lab beneath the Monastery of Stoudios in Istanbul so he can complete the plan he was working on before he was arrested.
Steve uses a radio artifact to contact Claudia inside of her bronze shell. Artie calls to tell Steve that he has found Joshua but that he'll have to visit him in person to get the blood sample. Once Artie signs off, Steve lies and tells Claudia that she's safe for the moment.
Once he gets his half of the Philosopher's Stone, Sutton takes Charlotte and the agents to the Monastery and the hidden lab. He bribed the authorities to stay away from it and has come back from time to time to try and find a way to break the curse of immortality. Pete and Charlotte go in one direction, with Pete taking her half-stone, and Myka and Sutton go the other. As they search, they hear Nick scream and Charlotte runs off to find her son before Pete can stop her. Pete finds his partner, who admits that Sutton got away from her, and they enter a central chamber decorated with runes of life. The stele is on one wall, but a trapdoor opens beneath the agents, dropping them into a chamber below. They're knocked out by the fall and Paracelsus comes over and takes the half-stone from Pete.
At the warehouse, Steve attempts to keep Claudia from disintegrating further by putting her in the airtight bronzing chamber and using an artifact to suck the oxygen out of the air. It doesn't work, but Artie arrives with the blood sample and injects it into Claudia. The disintegration slows down but Artie warns Steve that they've only delayed the process for fourteen hours.
When Pete and Myka wake up, they realize that Paracelsus has their half-stone and climb up to the trapdoor.
Sutton and Charlotte find Nick in Paracelsus' lab. The alchemist uses an artifact net to immobilize Sutton and takes his half-stone. Paracelsus then recreates the experiment and invites them to breathe the fumes again so that they can regain their mortality. With no other choice, the family does so and Paracelsus vows to have his revenge on Sutton for turning him in. The alchemist draws a gun and tries to shoot Nick, but Charlotte throws herself in the way. Shot, she falls to the floor.
Pete and Myka arrive and Paracelsus uses a metal rod to deflect the Tesla blasts. He knocks down the ceiling supports, grabs the Stone and the bowl, and runs out. While Pete goes after him, Myka tells Sutton and Nick to get Charlotte out while she recovers the stele. Pete loses Paracelsus in the chaos and comes back just as a support falls on Charlotte. Sutton apologizes to his wife, who tells him to get out before it's too late and save their son. With her dying breath she tells Nick to save her life now that he has a mortal life. Myka returns with the stele and they get out as the monastery comes down around them.
At the warehouse, Kosan meets with Mrs. Frederic and explains that the Regents have agreed to access the redacted files. To do so, they must rely on the Keeper, the human being who acts as a living repository of the Warehouse memories. Abigail comes in and apologizes to Mrs. Frederic for the deception. She then uses a Hawaiian palaoa artifact to access the memories and confirms that the Regents bronzed Paracelsus because he threatened all of mankind with his plans.
The agents return to the warehouse and use the stele to restore Claudia. Realizing how close his friend came to death, Pete insists that Myka begin her cancer treatment so that he won't regret all the years that he wouldn't have without her. Myka agrees while Claudia realizes that she can sense the Eldunari. Kosan and Mrs. Frederic arrive, and Mrs. Frederic explains that she is losing the mental struggle for control of Warehouse 13. Pete wonders how that can happen since Mrs. Frederic and Claudia have been co-existing for moths. Mrs. Frederic tells them that Claudia is the future and that she is fighting and losing her battle against the past Caretaker of Warehouse 9: Paracelsus. The strain increases and Mrs. Frederic collapses.