Nina retrieves a copy of the First People book, in German, from a safe at Massive Dynamic. Later, she and Olivia discuss the mystery of multiple authors writing the same book. Nina wonders if the other Olivia's journal might shed some light. Olivia says it doesn't.
Olivia brings up Bolivia's feelings for Peter. She'd understand if he felt the same. After all, "She's like me, but better." Bolivia has a mom, real friends, and no history of childhood experimentation. She even wears a dress on occasion. Nina urges Olivia not to make the mistake she and Bell made, never honestly acknowledging their feelings for each other. Ask Peter how he feels.
In his office, Dr. Warren Blake opens a birthday package. When he pulls the little rag doll's string, it blasts blue powder! He collapses and dies horribly. Later, Walter determines that the mysterious powder dissolves bone matter but is non-reactive with everything else. Olivia finds a card reading "From Madison."
Peter brings Olivia coffee as she looks at surveillance footage from the post office where the package was traced. She sips, then checks the cup. It has milk in it.
The doll contains a small canister, made by the U.S. military. They ID a suspect, former Marine Aaron Downey, and raid his house, but he's gone. The agents find a cache containing three powder canisters. Three others are missing. Peter spots Downey, who flees and gets hit by a car. He's in a coma. Walter might know a way to question him, but he seems uneasy.
Earlier, while searching Downey's home, Olivia asks if Peter still thinks about her. Meaning Bolivia. He knows Olivia takes her coffee black with one sugar, but today he brought it with skim. That must be how the other Olivia likes hers. Olivia remembers other differences he mentioned, like her easy smile. Peter just wanted Olivia to understand that he thought he'd brought out another side of her. He doesn't want to be with "her" more than with Olivia. Sorry about the coffee.
Downey's ex-wife explains that Aaron left the Marines for a lucrative private contractor job overseas. She got pregnant after that, but seven months along, the baby died. Aaron had passed some DNA pathogen on to the baby. He blamed the overseas work, a weapons project Dr. Blake oversaw. Aaron said that he'd kill Blake, but she never took him seriously. Their child, Madison, had a bone disease that left her without a skeleton. Other men in Aaron's unit lost babies the same way.
Just then, Walter calls Peter. He's stranded in New Hampshire, out of gas. Olivia and Peter rescue him, and he explains about a Cortexiphan subject named Simon, who developed the unintended ability to read minds. It's probably dormant, but if Walter can reactivate it, Simon can read Downey's mind and learn about the next attack.
But Simon's ability is actually out of control. When they visit his remote Vermont home, he's relieved to meet Olivia, because he can't read her. (Sometimes Cortexiphan kids are immune to each other's abilities.) The Bishops wait outside while Olivia talks to Simon. Too many thoughts make him literally sick. She looks at his drawings of a pretty woman. He says he lives here, alone, because it's quiet. But he reluctantly agrees to help.
After a mighty mental struggle with Downey's scrambled mind, Simon gets the names "Maryann" and "Project Jellyfish." The latter must be the weapons experiment. Broyles learns of a second attack, on three defense-company executives. Olivia asks Simon about the woman in his drawings. She works at a coffee shop near his house, but he only drives by. His ability prevents him from getting close to anyone.
The three men in the Project Jellyfish field tests survived because they were inoculated, but the toxin affected their unborn children. DoD records show Downey got a huge cash payment - and some government land south of Boston.
That's where Downey's two mates are trying out their invention, a canister-holding vest with a handheld trigger. Next morning, the team finds the test vest, along with newspaper clippings about Congressman Jim Thorn (a senior military adviser during the Project Jellyfish era) and a floor plan for the Maryann Douglas wing of the Fine Art Museum. "Maryann"! Thorn is having a fund-raiser there, right now.
At the museum, Olivia looks stunning in a gorgeous dress. She'll have to make a complicated shot to stop the vest-wearer. Simon's pretty sick but soon finds one suspect. Unfortunately, he's not wearing the vest. That guy's heading upstairs when Simon "hears" him worrying about the plan. Olivia races up the staircase as the guy brandishes the trigger . . . and she shoots him! Afterward, Peter brings her coffee: black, one sugar. He says she looks great in the dress.
Olivia takes Simon home and says he should talk to the coffee shop girl. Explaining he read Peter's mind, Simon hands her a folded note.
Nina gets an idea while studying the First People books - and decodes the name "Sam." As in Sam Weiss, the mysterious bowling-alley manager. Visiting him, she asks why it seems that he wrote all the First People books, and what's the device for? He says that she knows he's not supposed to get involved. Besides, she should worry about Peter Bishop. Whatever frequency Peter's vibrating at will determine how the machine reacts. His frequency depends on whether he ends up with this Olivia or the other one. Whichever he chooses, her universe will survive. Nina knows he'll pick their Olivia. Sam has his doubts.
Olivia unfolds Simon's note: "He still has feelings for her."