Late at night, Olivia picks up a prescription and takes a pill right away. Walking home, she spots Lincoln in a diner. She explains that she was out walking because she had a migraine. The fresh air helps.
Lincoln says remember when she asked if he was freaked out? Well, he used to believe he understood the world, but now . . . Olivia says that eventually it will just become your life.
A man named Jack walks home nervously. His wife calls, and he says he thinks he's being followed. She hangs up and calls the police. Jack gets to his building - and something invisible tackles him. The cops find him, dead. His skin and hair have turned white. One officer senses the shadowy attacker and fires repeatedly, but no one's there.
The next morning, the Fringe team investigates. Olivia asks Astrid whether all the things they see ever get to her. Astrid says yes; if she hadn't seen an agency shrink, her head would've exploded a long time ago. Who does Olivia talk to? No one, and Olivia's starting to think that's weird. Meanwhile, Lincoln spots blood on the steps.
At a secret lab in the sub-basement of an apartment building, a shimmering outline in a tank slowly becomes human. A young man emerges. Later, in the building's elevator, he almost speaks to a woman, but doesn't. Another man arrives and chats with her. They leave, and the tank guy slowly vanishes as the elevator descends.
At Harvard, Walter finds a mucus-like residue on Jack's body. They're chromatophores, cells found in animals like octopi and chameleons that can translocate pigment, allowing them to blend into their backgrounds. Astrid traces the blood's DNA to a New York hospital: Baby Boy Bryant, born July 26, 1989, and died four days later.
Lincoln and Olivia look at the records. The baby died of complications from an undiagnosable genetic abnormality. Olivia gets another migraine. A nurse who was at the baby's birth tells them that the infant was very pale, and the OR lights burned his skin. When they carried him out after he died, she thought she heard him cry. A private insurance company, Cyprox, took him to be autopsied. Olivia later tells Lincoln that Cyprox paid her mother's medical bills when she was dying of cancer. It was a subsidiary of Kelvin Genetics - which became Massive Dynamic.
At MD, Nina confirms that chromatophore cells were implanted into the baby's system, allowing him to blend into his surroundings. Lincoln observes that would make him a perfect spy or soldier. The chromatophores somehow offset his condition, which is why he survived. Nina says that neither she nor William Bell knew about Eugene, the researchers' name for him, until a fire broke out in the lab ten years ago. Obviously, Eugene didn't die after all. She sends his files to Walter.
Lincoln visits Peter. They discuss the machine - and Olivia, who's made quite an impression on Lincoln. That's OK, because she's not Peter's Olivia. Then Lincoln is summoned to the lab. Walter realizes that the mucus is a conductor, allowing Eugene's chromatophores to absorb pigment. Meanwhile, Eugene kills the guy from the elevator and drains his pigment.
Walter explains that the chameleon man is dying. He's attempting to reverse what was done to him, but his body's reverting to his original deadly condition. Through a cute demonstration with mice named John and Yoko, he shows they can use ultraviolet light to "see" Eugene. Broyles calls; there's another body.
At the apartment building, a search dog picks up Eugene's scent. The police and FBI evacuate the residents and search the darkened building with dog teams and UV flashlights. While Olivia's checking an area under construction, the floor gives way! She clings to the edge of the hole.
Eugene turns up, illuminated in Olivia's flashlight. He pulls her up but grabs her gun. Learning that he was indeed a military experiment, she insists they're not the military. Eugene lowers the gun. He's been watching others live their lives, all his life. To be looked upon by the right person, he says, to connect - that's when you exist. Olivia understands. She says if he treats himself even one more time, he could die.
Lincoln arrives, and Eugene apparently escapes. But as the tenants return, he walks out, visible yet unseen. Agents find his lab, with shelves full of personal items, souvenirs from each resident's life.
The next morning, Eugene gets into the elevator. The same woman says she thought he wasn't coming today. He's surprised. She says she sees him every day, but thought he might have been ill. It's too beautiful a day to be sick. The most beautiful, he says, adding that his name is Eugene. She's Julie. She smiles and leaves. Alone, he slides slowly to the floor.
Olivia tells Nina that Eugene's dead, then asks if the Cortexiphan trials could have stunted her emotions. Nina says no. They talk about finding where you belong in life. When the time is right, Olivia will know.
At HQ, Peter gives a puzzled Lincoln a small case. He leaves. Olivia arrives and says maybe she'll see Lincoln at the diner tonight. Maybe, he says, smiling.
Alone, Lincoln opens the case. Inside is a different pair of glasses. He puts them on.
Later, Lincoln waits in the diner. As Olivia heads out, gas seeps under her door, knocking her out. Two men in gas masks replace batteries in a pinhole camera and give her an injection. One says it's going to give her a hell of a headache. They depart . . . and Nina's there, looking at Olivia. She leaves, closing the door.