On a jetliner bound for Seattle, pilot Adam Ashby is preparing for landing when he clutches at his head as silver veins cover it. He gets up, confused, and staggers out of the cockpit while the co-pilot tries to land the plane.
Myka goes down to breakfast on her first day back. The others are having breakfast and Myka discovers that there's no chair for her. Leena quickly brings one over. Artie briefs them on Adam, who forgot how to fly his plane. Pete worries that they have to fly and Artie tells him they'll be perfectly safe. As Artie leaves with Steve and Claudia, Myka asks Pete if they need to talk about her leaving. Pete assures her that he's fine and they're back on the case.
In the warehouse, Artie tells Steve and Claudia that they're going to Boston to bid on a butcher knife owned by Typhoid Mary. The knife lets its owner transfer injuries and illnesses to anyone. Claudia is surprised to learn that Artie is sending her out in the field while he attends the funeral of a Regent member. She's thrilled when she realizes that she's the senior agent. Steve points out that Artie is sending him on a boring mission, but Artie tells him to worry about it after he comes back with the artifact.
In Seattle, Myka and Pete visit Adam, who now has the mental processes of a five-year old... and he's getting worse. Meanwhile, in the hospital's ER, surgeon Lisa Ward is operating when she's affected by the same thing as Adam. She's unable to complete the surgery and the other doctors rush to stabilize the patient.
In Boston, Steve and Claudia go to the auction house. Steve complains that there are no bad guys to shoot at and Claudia points out that they go after artifacts, not bad guys. Claudia finds herself bidding against another woman for the knife and finally wins. However, when they go to get the knife, the auctioneer informs them that it has been stolen and they have a bad guy.
Adam's doctor informs them about Lisa's case. The surgeon has only regressed to the mental age of a teenager... so far. Pete goes to check their backgrounds and see if there's a connection while Myka talks to Leena and sees if there are any memory-loss artifacts. Pete hesitates before he goes but then claims that he spaced off and walks away.
Steve and Claudia confirm that the woman who bid against Claudia didn't take the knife. They return to the auction house and check the time card records. A janitor, Owen Larsen, left early and has only worked at the auction house for a week. As the partners leave to check on Larsen's apartment, they're unaware that someone is watching them.
Leena doesn't find any artifacts that match the symptoms. She asks Myka how it is being back and the agent wonders why she's asking. Myka realizes that Leena has picked up something from Pete's aura and asks what it is. When Pete comes in, Myka cuts the connection. He shows her credit card statements confirming that Adam and Ward ate at the same restaurant the night that a waitress, Amy was murdered. Pete starts to leave for the restaurant but Myka asks him to be honest and say what he has to. He hesitates and then rattles off movie quotes.
At the restaurant, Pete tries to talk to the waiter, Ken. He finally gets around to telling Pete that Amy was a great girl and Ward and Adam were called as witnesses. The police have arrested Geoffrey Cedolia for the murder and he goes on trial next week. Pete reports to Myka, who informs him that Adam has forgotten everything, including how to swallow and breathe.
As Claudia and Steve watch Larsen's home and wait for him to report, Steve suggest that she meditate. She insists that she has mission experience and Steve points out that she doesn't have to be so insistent on being the senior agent when it's just the two of them. Claudia figures that he's hitting on her until Steve explains that he's a homosexual. They agree not to talk anymore.
Pete goes to the correctional facility to talk to Geoffrey and his lawyer, Sawyer. Sawyer suggests that the government prosecutor is scaring off the witnesses, but Pete insists that the patients aren't faking. The defense lawyer suggests that Pete protect Eric Bell, Geoffrey's best friend who can testify that he left the restaurant before Amy's death. The defendant's pregnant girlfriend was home asleep and can't testify on Geoffrey's defense.
Myka goes to see Amy's mother, who has been talking to the press and insisting that Geoffrey was guilty. However, she takes offense at Myka's suggestion that she might do anything to tamper with the trial. Courtney Moore, a local TV reporter, comes by for an interview. Amy's mother explains that Courtney has given her daughter's murder a lot of air time and is convinced that Geoffrey killed her. Courtney insists that her views know the truth about Geoffrey's guilt.
Steve notes that Claudia puts a lot of pressure on herself and wants to impress Artie. He points out that Artie wouldn't have sent her if he wasn't confident in her, and Claudia mentions that she was in an institution. Larsen arrives and he sprays Steve with mace and runs off. He runs past a car and the driver slams the door into his knee. It's Artie, who grabs the knife at the same time that Larsen does. Artie gets Larsen's injured knee and Larsen escapes before Steve and Claudia can catch him. Claudia figures that he came to Boston to spy on her and runs off.
Pete and Myka discover that Eric's mother Sarah has brought her son to the hospital. He's suffering from the same memory loss as the others. Myka figures that Courtney is connected to all of the witnesses. However, as the agents leave, Pete suddenly loses his memories and has no idea who Myka is.
When Pete wakes up in a hospital bed, Myka promises to fix everything. Disgusted, the younger-memory Pete says that things will never get fixed because his father recently died and isn't coming home. He talks about how it's hard on his mom, who tries to stay busy and doesn't see Pete much. When Myka reminds him of his sister, Pete says that she'll be going off to college in a few years and he'll lose her as well.
Myka goes to the news station to demand answers from Courtney. The news reporter has no idea what she's talking about, but then regresses like the others.
Artie tries to use Claudia's laptop to track Larsen's cell phone. She returns and takes back her laptop, and then accuses him of spying on her. Artie explains that he just wanted to check on her on her first case as a non-apprentice, and tells her that he's proud of her. Claudia locates Larsen and figures out why he wants the knife, and Artie starts to leave. He tells Claudia that he's sure that she can handle it and goes home.
Myka goes to the correctional facility to tell Geoffrey what is happening. He doesn't know why Courtney isn't connected to the others, but says that when Sawyer stood up to her, she folded.
Claudia and Steve got to a medical center and find Larsen placing the knife in an unconscious patient's hand and then touching it to himself. When they come in, Larsen explains that the patient is his son and dying of leukemia. He couldn't let his grandson lose his father, researched cures, and found out about the knife. Now Larsen has cancer, but his son can protect his own son and things are fair. When he asks if they're going to arrest him, Steve echoes Claudia's earlier sentiments and says that they go after artifacts, not bad guys.
Myka goes to the station and reviews the footage of Sawyer's interview. She spots Sawyer wearing a tie clip and realizes that the defense lawyer was grilling Courtney. Everyone suffering from memory loss was questioned by Sawyer. Myka goes to see Sawyer and explains that someone is using him. He confirms that he received the tie clip as an anonymous gift, the same time that Adam lost his memory. She takes the tie clip and confirms that it has the initials WW on it. Leena confirms that it belonged to reporter Walter Winchell, and that he had a matching pair of cufflinks. Myka figures that it is a bifurcated artifact. The tie clip takes the memories and the cufflinks restores them. Leena has confirmed that a young cub reporter, Louis Thompson, worked with Winchell. Sarah bell is Thompson's grandson.
Myka goes to the hospital and the doctor informs her that Eric recovered and Sarah checked him out. As Myka goes, Pete asks to go with her but he realizes that she's leaving him just like everyone else.
At the Bell house, Myka confronts Sarah in the kitchen and asks for the cufflinks. Sarah refuses to help the others and Myka explains that Sarah doesn't want the police looking for the real killer... Eric. Sarah throws a switch to turn on the garbage disposal and threatens to destroy the cufflinks. She offers to leave and then send the cufflinks to Myka, but the agent warns that by then the damage could be permanent. Eric hears them talking and asks his mother what's going on. He says that it was a mistake for her to protect him. When Sarah argues with him, Myka shoots the switch, shutting down the garbage disposal. Eric takes the cufflinks and gives them to Myka.
Myka goes to the hospital and uses the cufflinks to restore Pete's memories.
Courtney interviews Sawyer and asks how he persevered, and he explains that he kept faith in his principles.
Geoffrey watches as his friend Eric goes to jail, and then is reunited with his girlfriend.
Larsen, his son, and his grandson enjoy quality time together while Claudia and Steve look on.
Myka apologizes to Pete for leaving without talking to him first.
Later, Myka reports to Adwin Kosan and the other Regents. She talks about how Eric had been dating Amy secretly. When she broke it off, he took Geoffrey's car to confront her and it ended badly. Sarah found out and sent the tie clip to destroy Geoffrey's case, thinking the memory loss was temporary. The Regents point out that Myka thought she was protecting them by leaving. Adwin asks if Myka feels she can handle the pressure and Myka says that she's okay. Satisfied, Adwin tells her that her trial period is over and welcomes her back.
Myka joins the others for breakfast.