We begin with a man getting a somewhat optimistic cancer prognosis—a 95% chance of survival. He takes the news stoically, silently. After seeing the doctor, he’s sitting at a bus stop when a man approaches him. The stranger begins spinning a dark prediction for the cancer patient’s future. He tells the man that he is in the 5% who don’t survive. A bus then passes by. When it is gone, the cancer patient is lying dead on the bench. (We know that he’s dead because, in TV, people don’t fall asleep after scary and mysterious strangers come speak to them.)

After the theme, we see a pair of booted feet passing through the crossworlds. It’s the other Astrid. She takes in the green statue of liberty, looking grim. Back on the other side, Fringe is freaking out that Astrid apparently took off to the other side without informing anyone. Broyles wants a team to retrieve her, but Olivia wants to go handle the matter privately.

Meanwhile, Peter and Walter are working in the lab. It is apparently an ordinary day (as ordinary as it gets for them, anyway). Peter wanders off to go to work on the machine, leaving Walter alone. The other Astrid enters the room, surprising Walter by correcting his pronunciation of her name. He then realizes that the woman is not his Astrid.

Following the commercial break, our Olivia and Astrid (henceforth to be called Astro as long as other-Astrid is present) return and are surprised to find other Astrid waiting. Astro is startled but thrilled to see her counterpart. Astrid seems highly agitated, talking about her mother’s death years ago. It seems that her father has just passed away.

Olivia’s phone rings. She has a case to take care of, and Folivia is on her way to sort out the Astrid situation. Olivia and Astro decide to take off while Peter, Walter, and Astrid man the lab.

At the crime scene, the dead cancer patient has bloody tear streaks on his face. Walter determines that the organs are not liquefied, but is not sure what could have caused it. Meanwhile, Astrid looks like she is struggling to understand how Fringe on our side works.

Yikes. Okay, an Observer just walked through a wall. He seems to think they have located “it.” He then disappears back through the wall. (Because Observers know everything, they must know they are on TV. Otherwise, why walk through a wall and into the open just to talk into their little communication devices?)

Back at the lab, Team F is examining the body. Olivia rattles off the victim’s identity. Walter has uncovered the killing agent, but it is a chemical compound that he has never seen before, one that should not even work. Basically, he was killed by a poison that no one invented.

Folivia walks into the room and says hello. Walter begins to berate her, but Astrid interrupts with a theory that sounds paradoxical and nonsensical, so naturally she’s right. In essence, the only way to concoct the potion is to know firsthand it can be done when it has never been done before. (It will be interesting, I think, to see how Peter reacts to Folivia when he had an affair with the other her.)

Elsewhere, a woman leaves a liquor store with a paper bag. But, oddly, she throws it in the trash. Then the killer shows up, telling her that she will eventually go back to alcoholism and ruin all of her loved one’s lives. He tells her there is no future, no past, only what happens right now. He then raises a strange device and sprays something in her face. (Yuck.)

At the lab, Walter returns some things Folivia left behind. She is happy that he saved it. She then informs Walter that the reason she got to him is that he likes her.

Erstwhile, Team F is back out in the field investigating the latest mysterious death. Peter grabs a DNA sample, finding hemorrhaging in the nasal passage. Walter is a little irked that Peter begins anticipating what he is going to say.

Once the body is back in the lab, Peter goes to work on it. Walter asks him to sharpen scalpels instead, however. Astrid makes the observation that Walter wouldn’t be angry if he didn’t care. She wonders why Walter doesn’t end his own suffering by treating Peter as a son.

The two Olivias are using this time to work together to go through files. Folivia testifies that he is cute, but she likes nice guys (assuming that Peter is crafty like Walternate). Olivia is determined to find a connection between the victims, which is the only way to find a killer.

At an airport, we next see killer man working as a security checkpoint guy. He holds licenses up to a strange glowing cylinder, as if testing for a reaction. When the cylinder glows, he writes down a name.

The next intended victim is subsequently seen in a parking garage, talking on his cell phone and being observed by, well, an Observer. The killer approaches him, looking dire. He tells him that being on the phone will cause an accident that leaves him handicapped. He says he will spare the man that misery and tries to spray him, but the guy runs—only to be hit by a car. Creepy.

Olivia and Peter then rush to the hospital. The man has survived, but he is paralyzed as was predicted. The man reveals that his situation was predicted. (Funny, now I’m flashing back to the last episode.) Olivia asks if he knows the other victims, but no luck. He does explain that the man wanted to put him out of his own misery, and he wishes it had worked.

Back in the lab, Astro offers Astrid coffee, which is rare where she comes from. Walter and Folivia are still bantering. They talk about the killer, who is “compassionate.” Just then, Astrid finds that all of the victims went through an airport recently, noting that they may have all been screened by the same TSA agent.

Peter and Olivia next visit the airport, but the agent gets spooked. Unfortunately, another agent stops them from getting through. (Way to go, airport security.)

As it turns out, our TSA agent in question once worked at MIT as a math professor before losing his mind. He eventually became obsessed with equations that would “flatten” space and time, enabling him to see past, present, and future simultaneously. Then, finally, he left MIT and returned to his lake house at Reiden Lake. Peter begins hatching a theory that Observers are involved, judging by the similarity between their ability and the suspect’s.

Back in the lab, Astrid is still mourning her father. She feels that she couldn’t please her father because of the way she is (logical, analytical, almost never making eye contact). She wonders if he would have loved her more if she were normal.

Up at Reiden lake, Peter and Olivia approach the suspect’s lake house. They enter the house with guns drawn. It’s an empty residence, with all kinds of equations on the walls. They learn that the suspect’s father and twin brother were killed in an accident, and that he is obsessed with history’s famous “saviors.” A picture reveals that the suspect has an elderly relative.

The suspect (Neil, I think?) is meanwhile at his mother’s house. He puts his little magic blue thing away in a safe before grabbing a gun. He heads for the door, looking resolved, as his mother pesters him about where he is going. He says he is going where he belongs. He also tells her he heard her the night “Alex” died, that God took the wrong one. He believes he has earned the right to have survived. She tells him she is sorry. But he says that her disapproval was always just inspiration to try harder. It appears he knows the FBI is on its way.

As Neil keeps talking wildly, Olivia and Peter enter the house. Olivia calls for him to surrender, but he turns with his gun drawn, forcing her to fire and kill him.

Back at the lab, Astrid says goodbye, permitting Walter to hug her. Folivia is also on her way out. She shows Walter that her mysterious box holds candy. It seems that he has somewhat forgiven her, as he gives her candy for the road, as well. Astro bids her counterpart goodbye, assuring her that her father is not close to her, either. Her father is a complex man, who does not really show emotion. It was not Astrid’s fault that he didn’t show love.

Later, Astro goes home to see her father. Apparently, she was not telling Astrid the truth, as he seems to be a warm and affectionate person.

Later, we see the suspect’s mother dozing in her chair. Two Observers are moving about in the house. They take the blue thing from the safe. (One is the Baldfather.) They say it belongs to September, who lost it in 1985 when he did not save the boy. (Buddy’s name is September? Weird.) The other Observer also tells the Baldfather that Buddy did not obey his instructions, and Peter Bishop has returned.