The first scene begins by showing the unsub fabricating a pipe bomb. There are textbooks and notes laying around him on the tables. He attaches the bomb to an umbrella and makes a call: "There is a bomb, on a bus, in the city where it started. Get my message out. This is only the beginning. Until it is brought back under control, people will die.
In Quantico, JJ rushes to Hotchner when she gets the bomb threat report and the team meets in the conference room. There is a map of the USA on a big screen. Several coast-to-coast networks also received a very similar call and message, which had not been recorded or scripted, indicating the unsub is pretty confident and he wants attention. Hotch believes he is a personal-cause bomber.
In Seattle, Washington, the unsub gets on a bus. Although it is sunny outside he is wearing thick black leather gloves and carries an umbrella, but not one really seems to notice. He drops the umbrella on the floor and exits at the bus stop. Then he takes a detonator out of his coat pocket and presses the button. The bomb explodes and, while a shocked crowd slowly gathers, he walks away and drops the detonator on the ground. So Seattle is where it all begins. Morgan mutters the only things that began in Seattle are grunge music and overpriced coffee.
The bomb killed two people on the bus, the driver and a seven-year-old boy. An elderly woman had found the umbrella on the floor and gave it to the boy to take to the driver.
JJ goes to talk to the passengers and map their seating locations on the bus, while the teams figure out the unsub had used a limited-range detonator - similar to a garage opener that only works from a short distance. Gideon enters the bus. They conclude they need to hold a press conference to get the unsub to call them, so they pretend they don't yet know for sure if it was a bomb or mechanical failure, and they also do not talk about or release the unsub's message, so as to stress the unsub. Cassandra Mollet, ("Call me Cassie"), the bomb technician, reconstructed the bomb and, upon closer inspection, Reid sees there is a drawing of a robot with an arrow through it engraved on the end cap of the pipe-bomb. Morgan calls Garcia and, after some flirtations, she goes to work and finds two previous anti-technology cases in the Seattle area. One was a young man smashing computers to bits in a Tacoma, and a second case with floppy disk bombs were used. With the last case, there also was a note stating, "You'll be as obsolete as your graveyard technology. FFT Brigade." And there is a picture of a robot with an arrow through it underneath. Bingo. The unsub has knowledge of the area, and he probably lives in Seattle. The team is not sure if he intended to kill people because the bomb was built to do minimal damage and only had a short range. He probably wanted to install fear for technology into the public.
There are four types of bombers: criminal, group cause, psychologically disorganized and personal cause. This unsub clearly has a personal cause. Reid describes the Unabomber, who had fantasies of becoming a woman. He even applied for a sex change, but changed his mind halfway and shortly after he started making bombs. The team continues with constructing a profile. This unsub is male, lives alone, and is self-employed, highly organized, and very meticulous. He seems odd to the people around him. No one will be surprised when he gets arrested and, when they are told what it's for, he very likely also has a temper because he is known for outbursts. In fact, the unsub becomes so stressed that no one did as he said that he calls the tip line.
The call gets handed to Gideon. The unsub is angry – "we called all networks, we warned you! Where is our message?" Gideon asks him what he can call him. The unsub replies with, "FFT Brigade – it's a major organization, we have hundreds of members." When Gideon keeps pressing on about his personal name, he tells Gideon, "You may call me Allegro." Gideon tells him, "Let's talk about your message…where can we meet?" But Allegro responds with an unnerving message that he will be here when you arrive.
Allegro then detonates another bomb at a gas station, and Gideon hears the explosion through the phone. When Gideon arrives, Cassie is already on the scene. The same kind of detonation device was used and, in this case, the main goal also didn't seem to be to kill a lot of people. The gas station was closed and the worker had left. Gideon looks for the message, and finds a large metal box (after the bomb squad clears it). Inside the box is a manifesto and a drawing of the robot with the arrow through it. The unsub demands they stop all automated machinery that replaced working Americans within a week.
Reid remembers Allegro is character in a book, a novel, called "Empty Planet" and it was written by David Hansbury. Reid described the story about robots taking over the world; the hero of the book is 12-year-old Allegro. He is the one who saves the world. The team discovers Dr. Cooke was on the bus, a scientist who had invented a machine that mimics the human reproductive system. Allegro and his army also destroyed the scientists in the book, and the umbrella was initially found under Dr. Cooke's seat. It looks like Dr. Cooke was the unsub's intended target on the bus. So they make a reluctant Dr. Cooke come to the office. He said it's ridiculous that someone wants to kill him because of his work. It's can't be a religious group - no scientific knowledge precluded existence of God. And it can't be someone worried with the ethical side either – it doesn't involve manipulation of existing creatures; he is merely inventing a new electronic one. When they ask Cooke about Empty Planet, he replies, "I'm friends with the author". Her name is Ursula Kent – she is a literally professor here in Seattle.
Cooke really doesn't believe the unsub has it in for him. Gideon asks if he thinks it is a coincidence that he was on that bus and knows the author. Cooke quotes an MIT scientist regarding coincidence. Reid begins to explain the quote to Gideon, but is briskly interrupted. "I understood him!" Cooke leaves, telling them he doesn't want to be followed by a goon squad. Gideon is annoyed and asks Morgan, "Ever talked to someone who wants to continually show you he's smarter than you?" Morgan gestures toward Reid. "Every day."
Professor Ursula Kent also happens to lecture at the same university where the floppy disks exploded. Gideon and Reid pay her a visit, but stops by a book store so Reid can buy a copy of her book to reread it because he was only six years old the first time.
Gideon believes Cooke really is in danger, and he needs someone to tail and protect him. And he wasn't wrong. Cooke parks his car and as soon as he gets out of his seat, the blows up. So, in comes the bomb squad again. The unsub had used a simple compression detonator in which the device arms when pressure is put on and detonates when pressure is taken off again. Gideon defends his team, telling the others that Cooke had refused security, and he had given him security anyway but it wouldn't have helped. The detonator was already being installed in the car when Cooke was meeting with the BAU.
The unsub calls Gideon again. Who now has a much better idea of who he is talking to and what it's about. He tells him he is living a novel. The unsub answers with "Well, I'm going to visit an old acquaintance now, I'd invite you but you will al be very busy. I want my manifest printed." They get a report that there is a pipe bomb found at the waterworks, and Reid and Gideon go see the professor. They tell her that her book has become a significant part of their investigation. The unsub wants to save humanity. He's killing people for the sake of your cause. The professor tells them the book is a fantasy. They counter with "Not to this man. Dr. Cooke was murdered by the bomber one hour ago." The professor is visibly shaken.
The bomb squad safely removes the bomb at the waterworks, but immediately goes to the next bomb report at the post office. Back to Gideon and Reid – the upset professor plays with her necklace, which has a pendant of a robot with an arrow through it. She tells them she got it from a friend, James, and that it was the inspiration for writing "Empty Planet." She is surprised that they think the unsub could be one of her students.
"In my area, technological advantages are sort of art objects." But they let her read the unsub's manifest, and asked her if the writing seems familiar. She doesn't recognize anything in the manuscript, apart from the plagiarized parts. Meanwhile, the bomb squad is still busy disarming small harmless bombs on four locations in the city. All government buildings, nothing that is involved in technology. "He's distracting us and keeping us busy."
Professor Kent says she always has two guest lecturers: Cooke on artificial life and Brazier on artificial intelligence. Brazier is his next victim. Morgan is just in time. Professor Brazier is about to leave the parking garage. He makes her stop and tells her not to touch ignition and to put car in park and not to move. There indeed is a bomb under her seat. Cassie hopes this again is a simple lever action compression detonator, in which case they should be okay. But if there's mercury, they have a problem. Morgan does not want to step away from the car and leave the professor alone, so he stay by her side all the time at the risk of being blown up.
Cassie inspects the bomb under Professor Brazier's seat with a mirror and concludes that it is a simple lever. She safely removes the bomb. "Good," says Gideon when he hears the news. "Now blow the car up. Let bomber think he succeeded."
Reid asks Professor Kent why she didn't ever write another book. She replies, "This was the only story I needed to tell." She tells them will try to think of any male students she'd had with a temper. Gideon and Reid leave, and the professor orders Kenneth Roberts's file, thesis, and student paper from last year to be pulled from records. She thinks she did recognize something after all. Then throws her own book in the trash.
Reid summarizes the book for everyone. At the end, Allegro killed his biological mother because she has turned into a robot as well. But strangely the mother was very proud of him; she saw it as proof she had been right to give him up in the first place. He tells them the whole book had been written through her eyes. Therefore, the unsub will kill his mother, and Professor Kent is his mother.
Kenneth managed to get into the professor's office and sees she had read his manifesto. She tells him, "Kenneth, I think you misunderstood. It's a work of fiction. Just a story." Kenneth says his mother died when he was eight. Later, his dad needed a blood transfusion and he learned they had nothing genetically in common. "Before my dad died, he told me I was adopted. But the records were sealed." Kenneth had been adopted in Ohio. And he read an article about Professor Kent, which said she had given up a baby for adoption and that was the inspiration for her book. Kenneth wanted to know if the adoption was 26 years ago, then he takes her hostage in an auditorium as the team is closing in on them. Kenneth asks her how she could not recognize him since he sat in her class for a year. The professor tells him the baby she had given up was a daughter. "I know the pain. I'm not lying, but you're not my son. I will do everything I can to help you find your birth parents." Kenneth is not happy with that answer and, when the team rushes in, he warns them he has a bomb. When the professor sees the sniper's laser pointer appear on Kenneth, she throws herself in front of him, saving his life but is hit in the shoulder. Gideon holds her and sits with her, telling she will be fine.
On the plane back to Quantico, Morgan talks to Gideon: "I hear you were worried about me." You said, "A young man that I greatly admire and respect is putting his life on the line." Gideon tells him that what he did with the bomb was stupid. Morgan defends his actions. "I couldn't leave her by herself like that." Gideon looks at him. "I didn't say you were wrong."