After Senator James Van Horn's car is broadsided by a truck, Broyles meets the senator's wife, Patricia, at the hospital. As doctors work on Van Horn, Newton charges in and starts shooting. Broyles hurries toward the sound as Newton wheels the senator out, still shooting. Broyles wings him, but Newton shoots the senator in the left eye and flees. The senator bleeds mercury. He's a shapeshifter!
At Massive Dynamic, Peter tells Nina his doubts about Walter now being the owner. But Nina believes in Walter's brilliance. Meanwhile, Walter lectures a group of MD scientists about brain physiology while tripping on LSD.
Later, Broyles says that they need to find out how long the senator has been a shapeshifter and why. He'll call the CDC and order blood tests for everyone on Capitol Hill. Walter examines the shapeshifter and tells the agent assisting him that the thing is part machine, part organic. Peter comments on that single shot through the eye. Walter thinks it might be the location of a power source. Maybe they can fix it.
Bolivia calls Newton, who explains that Van Horn was a senior operative. He knew everything, even about Bolivia. But he's dead, so her cover's safe - for now.
Bolivia asks what that means, and Newton sneers that her mission probably involves gaining Peter's complete trust. Newton thinks that, somewhere deep inside, Peter senses she's not HIS Olivia. Bolivia bristles, but Newton insists that she's in over her head, is not fully committed to this task, and will fail.
In the hospital, Walter pokes around in the shapeshifter's eye socket. He wants to take it to Massive Dynamic. The corpse's hand twitches and its eyes move. Walter says this tin can is still kicking!
Astrid brings a box of stuff to Walter, who plans to use visual stimuli to help find the shapeshifter's data storage unit. Meanwhile, Bolivia and Peter search Van Horn's office. Newton calls Bolivia, who tells him that the shapeshifter is alive at Massive Dynamic. Peter finds files on Olivia, himself, Walter, and all their cases. Van Horn knew everything.
In Yonkers, New York, a man named Ray answers the door during dinner with his wife and young son. It's Newton, there to give Ray, a shapeshifter, his assignment to retrieve the other shapeshifter's memory chip from MD. Ray hasn't seen Newton in five years; he seems reluctant to do the job and move on from this life. But he does as he's told.
At Massive Dynamic, Broyles reports that everyone on the Hill checks out. Peter says that Van Horn collected intel on them for the last two years, but they don't know how the shapeshifters get orders or who they work for. Walter says let's just ask the shapeshifter. He and Astrid demonstrate how it responds to personal stimuli, like a picture of the senator's wife. They can use that emotional tie to revive its neural pathways and retrieve the info. Bolivia objects that Patricia is a civilian. Broyles says that if Patricia agrees to help them, he'll trust her.
Wearing a police uniform, Ray opens a safe and removes his gun and shapeshifter device. He tucks in his son and leaves, sadly.
When Patricia talks to the Van Horn shapeshifter, Walter detects increased neural activity at the base of its spine. But they pull the plug after the shapeshifter starts reciting numbers and words, and Patricia freaks because it's referring to the Van Horns' anniversary. Walter says the shapeshifter is too damaged.
To get everyone out of the lab, Bolivia suggests taking a break. In the cafeteria, Astrid's mention of a stegosaurus triggers an idea for Walter, who heads back to his lab. Ray gets into the elevator, and Walter babbles that the stegosaurus had a brain in its ass.
Meanwhile, Peter tells Bolivia that Patricia Van Horn must have noticed something weird about her shapeshifter husband. He wonders if she just found ways to explain it to herself . . . kind of like he's been doing with her. Bolivia asks, "With me?" Peter says that ever since she got back from the Other Side, it's like she's a completely different person. Astrid walks up, but where's Walter? Peter and Bolivia take off.
Ray bursts into Walter's lab, pulls a gun on him, and takes the chip from Van Horn's spine. Walter grabs an instrument and stabs Ray. Ray smacks Walter around. Downstairs, Peter and Bolivia watch Ray leave the elevator. Peter sees mercury smeared on the buttons and realizes that cop is a shapeshifter. He finds Walter and checks the security cameras to try to identify the cop.
In Yonkers, Ray gives Newton the chip. He looks toward his house, and Newton says he understands why Ray hesitated before: It's because of his family. Newton tells him that he'll have another life, but Ray can't give them up. Newton shoots him and puts him in the trunk of his car just as Peter and Bolivia pull up, firing.
After a crazy car chase, Newton crashes. Bolivia takes the chip from him, telling Peter she can't find it.
Bolivia visits Newton in his cell and gives him a microchip. He taunts that there's a line she's not willing to cross, and that will be her undoing. But that's not his problem anymore. She walks away. Newton eats the chip and dies.
Bolivia texts Peter, asking him to come over and talk. He does, but she says she lied. She doesn't want to talk. They kiss and start making out. Privacy, please.