The episode begins giving Peter giving Diana the U-Boat manifest and asking her to take it home and translate the entries into English. She is then to give it to Matthews. Neal is aware something is going on; in fact he is visibly shown suspecting it. He sends Mozzie a text - "The Swap is on.” Just before they can snag her briefcase, Diana's girlfriend Christy walks up and ruins the plan, much to their dismay. The new plan is to get a look before the manifest makes its way to Matthews, and they plan to put it into implementation. Meanwhile, a major publisher asks the White Collar division to look into one of its top journalists, Helen Anderson about protective detail, as they suspect something is amiss. Anderson (who is reluctant about being protected) tells Peter and Jones a lot of her stories draw attention.
She has no interest in being shadowed by Jones; a fact she makes amply clear. Outside the office, her publisher tells them to keep her alive, as the kind of work she is doing is dangerous. He offers his assistance, to this endeavor. Since Anderson fired her assistant, Peter's idea is for Diana to be her next one, so they can manage to keep a close watch on her. Diana is already a fan of Anderson's work, and jumps at the opportunity to keep watch. Diana can't let Anderson know she's an agent, as this would prove counterproductive with Anderson refusing to tolerate her presence. Thus she's going to have to pretend to be from Anderson's part of England, as that would establish a common ground between the two, and would create a soft spot of sorts for her in Anderson’s heart. They tell her how brutal Anderson will be to work for, but Diana is unperturbed. Meanwhile, Sara asks Neal for help beating a security system, as he is just the man who can manage to accomplish the feat. The couple has also been invited to dinner with Diana and Christy. Meanwhile, Anderson tries to boot Diana for being "overqualified and too old".
But Diana works her magic, and talks her way into being hired. Diana has two leads for the team, men named Sullivan and Vaughn. They work for one of the world's leading pharmaceutical companies, P & V. Meanwhile, Peter and Neal posed as FDA agents show up in Sullivan's office unannounced. Using text messages and the internet, Jones gets Sullivan's secretary to leave her post, thus allowing them a free pass. While Peter vamps, Neal goes to the other room. He finds a memo with several redacted lines. Meanwhile, at the FBI office, Neal peels the back off the memo. They see the drug mentioned is called Zybax. Meanwhile, Diana tells Peter she's battling to keep up with Anderson, as she is quite the woman to work with. Suddenly, while looking at one of the pictures, she realizes the people watching Anderson have a key to her residence, much to her dismay.
Although warned about the impending danger, Anderson has no interest avoiding her own residence; in fact she is adamant about not doing so. Diana overhears a conversation where Anderson tells someone at P & V about how dangerous things are getting. She adds, "Let’s take them down." Meanwhile, it is shown that Zybax is drug designed to combat drug-resistant infections. The company is going public this month. For some reason, they ran a cost analysis for taking it off the market. Diana calls to say Diana's source inside P & V said people have been dying "over this." Anderson tells Diana she's taking the night off. Diana confronts her about meeting with the source and asks to be taken along. Anderson wants Diana to move her son Charlie's party, buy him a new present, change her locks and do some translations if she wants to tag along, although a daunting proposition, Diana reluctantly agrees. Meanwhile, Peter delegates Diana's jobs for Anderson to members of the team, so they can be expedited. Elizabeth works on the party. Mozzie does the new locks for Anderson's town house.
Peter fins the present for Charlie. Anderson is stunned Diana finished everything on her list and that too in such a short span and more importantly, she managed to do them quite efficiently. Since this is the first time Anderson is meeting this source, she makes Diana wait at a good distance, so as to not raise any suspicions. During the meeting, she notices a shadowy figure nearby. Diana chases the person away, but not before the source gives Anderson a flash drive. Diana comes home to Neal and Sara waiting with Christy. Over dinner, Christy (a doctor) says she'll check the mysterious numbers on drive at the hospital the following day. Neal talks to Christy. He also searches the apartment for signs of the manifest. Back at home, Mozzie interrupts Neal and Sara fooling around. She leaves. He tells Mozzie that Matthews must now have the list. They want to swap briefcases out at the airport when Matthews leaves town. The source's numbers match sample packs of Zybax in the hospital database. However, P & V reps came in and swapped out Zybax for other samples of the same drug. They wonder if P & V tried to swap out a bad batch of the drug with a fresh one, using faulty packaging as the reason.
Neal doesn't think they could have gotten every single pill from the original batch out of the hospital. Anderson's source tells her he has a "smoking gun" memo. The plan is for her to get the memo herself at P & V headquarters during a launch party. Diana tells Peter the memo is supposed to be evidence of a recall signed by Sullivan. Peter tells Neal he's worried Anderson's source could be revealed if Anderson is being followed by P & V. Jones tells them they've discovered the leak is Casey Mendel, P & V's head of Research and Design. At the launch party, Anderson is told to keep her distance while she meets her source. At the same time, Peter and Neal go to Mendel's home and see he's been found dead. A man quietly tells Anderson a room number where she can find the memo. Peter calls Diana to tell her the launch party was a set-up.
Diana rushes upstairs. We see Anderson corned in the room by a man who pulls out a hypodermic. Just before he kills Anderson, Diana rushes in with her gun drawn and saves the day. Back at the station, Peter tells Diana that Zybax causes brain hemorrhages when paired with certain medications. P & V's plan was to shut down Anderson and see if they could get the bad drugs off the market. Anderson stops by the office and tells her she wants her back as an assistant and offers her double what she's being paid. Diana turns her down; she tells Anderson to hire back her old assistant. Peter walks away with Diana, whispering he made sure Matthews kept the list safe. Mozzie calls Neal to tell him Matthews took an earlier flight. Neal realizes Peter is on to him.