Simon is in the bar car of a train heading for Los Angeles and flirts with a woman, Camille. He claims to know what caused the flashforward and she doesn't believe him at first. He has her look him up on the Internet and confirm he's an award-winning quantum physicist. After flirting with her, Simon describes his theory about the flashforward, involving Schrödinger's cat.
Medics bring a badly wounded Janis Hawk into the hospital where Olivia and Bryce begin operating on her.
Simon talks about the concept of quantum uncertainty, where objects can exist in an indeterminant state, neither alive nor dead, until the observer reaches a conclusion. He gives the example of Schrödinger's cat, kept in a box with poison. Until the observer opens the box, the cat is both alive and dead.
The surgical team manages to stabilize Janis. Afterward, Olivia tries to call Mark but doesn't get an answer. She leaves a message about Janis and then says she loves him.
Lloyd Simcoe performs Dylan's favorite card trick again and suggests that they live at his home. Dylan refuses and turns sullen. Bryce comes in and reminds Lloyd that it's Halloween, and Lloyd realizes he hasn't bought a costume for Dylan. As he goes to get one, Dylan keeps muttering, "It's my home, too."
Stan, Demetri, Gough, and Mark arrive at the hospital to visit Janis. Mark goes to find Olivia and ask her to give Stan and the others a status report. Stan thanks her and tells everyone to get some rest until they find a lead. When Demetri balks, Stan orders him to get out of the hospital. Once he's alone with Gough, Demetri suggests that they get out of the hospital like Stan said... and track down the people responsible for the attacks.
As Olivia rebandages Mark's flesh wound, she asks him what happened. He figures that the two attacks are related and Olivia explains that when she couldn't reach him by phone, she imagined the worst. Mark tells her that he's fine and Olivia talks about how they're both obsessed with the future of their vision and they need to focus on the present. Mark agrees with her.
Demetri and Gough meet with Dewey Martin at the morgue and go over the autopsy reports on the two attackers that Janis killed. There's nothing to identify them and Gough concludes that they're professionals. Gough notes that Demetri appears to be distracted and that he posted his lack of a flashforward on the Mosaic website. Demetri dodges his question and notices an ultraviolet tattoo of a blue hand on each killers' hand. He remembers that there was a blue hand note on Mark's Mosaic board and the word Baltimore next to it.
Lloyd finds a costume for Dylan and they go trick-or-treating in the hospital. Bryce accompanies them and Lloyd admits that his son may be mad at him for suggesting they go to Lloyd's home. He asks Bryce to have Olivia visit them so they can say goodbye before they leave.
As they get coffee, Stan apologizes to Mark for snapping him and says that they need to get back on track.
The next morning, Demetri and Gough return to FBI headquarters. Gough thinks that since the killers are Chinese, they're tied in with the CIA reports that the Chinese are responsible for the Blackout. Demetri notes that no one has attacked the CIA, and the two attacks came just after Mark announced their Mosaic findings at the Senate hearings. He believes that China is a dead-end.
Olivia examines Janis and confirms that she's okay. As Mark leaves for home, Olivia apologizes for being unable to be there for Charlie on Halloween. Mark assures her they'll be fine and promises to take pictures.
Demetri believes that the Baltimore reference refers to Baltimore St. in Los Angeles, and argues with Gough that they can check it out in an hour. Gough wonders if Demetri now believes in the flashforwards, and Demetri admits that it's the only lead they have.
Mark goes home and gets Charlie's costume ready. Aaron goes with them while Nicole stays there to hand out candy. Mark dresses up as character from Charlie's favorite cartoon and goes out with her and Aaron. As they walk down the street, a kangaroo hops by them: apparently the same one Mark saw after the Blackout.
Lloyd discovers that Dylan has disappeared from his room.
Stan sits with Janis and she tells him he doesn't have to do so. Stan believes she needs him and talks about her hospital gown reminds him of when his wife gave birth to their child. Janis remembers the flashforward of her pregnancy. As they talk, her blood count drops and Olivia is forced to take her back into surgery.
Camille goes back with Simon to his sleeper car and they have sex. Afterward, she talks about how in her flashforward, she'll be at Times Square with half a million other people celebrating when the time of the flashforward visions occurs. She asks Simon what he saw and he finally tells her that he sees himself strangling a man and smiling in satisfaction.
Lloyd goes over the hospital security footage and discovers that Dylan left the hospital.
Dylan gets on a bus without paying a fare and recites an address. The bus driver tells him to pay the fare or get off, but a gang member helps Dylan to get to the address.
As they check out Baltimore St., Gough gets a call that Janis is back in surgery. He tells Demetri who insists that Janis will be okay. He talks about the night before they both graduated from Quantico, when Demetri passed out drunk but Janis kept drinking without any ill effects. He figures that she's tougher inside then any bullet.
Olivia chooses a procedure to help preserve as much of Janis' uterus as possible. Bryce questions her decision and wonders if she'd make the same choice if she didn't know Janis personally. Olivia ignores him and goes ahead with the procedure.
Demetri and Gough find a stop sign on Baltimore St. with a blue hand decal on it that matches the killers' tattoos.
Dylan arrives at the Benfords' home and walks past a surprised Nicole. He goes directly to a cookie jar inside of a ceramic chicken, takes out a cookie and insists, "It's my home, too."
As they wait for Charlie, Mark and Aaron talk and Aaron says that he wanted to see Mark doing something normal. Mark starts to agree, but sees three men walking down the street wearing plastic masks. He remembers the men in his flashforward dressed the same way and yells at them. They run off and Mark chases after them.
Gough and Demetri realize that the three-fingered hand on the stop sign is pointing the direction they should take.
Mark chases one of the men into a cemetery and finally captures him. When he rips off the mask, he discovers that it's a teenager. The boy admits that he TP'd a house and bought the mask at a dollar store. Realizing the teenager isn't connected to his flashforward, Mark releases him and then gets a call from Nicole.
After driving three blocks, Demetri figures the number of fingers on the hand indicate the number of blocks. On a telephone pole they spot another hand with one finger.
Mark arrives home and tries to talk to Dylan, while Nicole reads Dylan's hospital wristband and calls Lloyd. Although he doesn't explain to Mark why he thinks it's his home, Dylan remembers his flashforward and how he lives there, gets a cookie out of the jar, and Charlie telling him that it's his house, too. He saw the house address on a label on the refrigerator. Charlie and Aaron come in and it's clear that Charlie and Dylan are friends. Lloyd arrives and thanks Mark for taking care of Dylan. He recognizes the interior from his own flashforward and that Mark is Olivia's husband. Olivia comes in and things become awkward. Aaron takes Charlie and Nicole into the next room while Olivia, Mark, and Lloyd discuss the situation. When things turn awkward, Lloyd thanks them and leaves with his son.
Demetri and Gough follow the trail of hands to an empty house. They find blood, empty bottles of alcohol, and drugs. There are also three sheet-covered corpses. Each one has blue-painted hands.
Stan visits Janis and brings in the flowers that Maya sent her. Janis explains that due to the surgery, it's all but impossible for her to have a child.
After Lloyd is gone, Olivia tries to discuss the situation with Mark. He accuses her of bringing Lloyd into their home and hiding her knowledge of the man from her flashforward. When he asks her to be honest, Olivia asks him to do the same and wonders if he's hidden anything from her. He finally admits that he was drinking in his flashforward, but insists that he isn't going to start drinking again. Olivia says it isn't about the drinking, but about the lack of trust and the pain it caused the first time around. Neither one of them trusts the other now. He points out what she said at the hospital about living in the moment, but Olivia admits that was what she hoped for, and they may not have that choice now. She turns and leaves him alone.
Demetri and Gough call in a forensics team. Gough finds identification on one of the bodies and realizes that he's Ian Rutherford, part of the Rutherford case that he saw in his flashforward when he was discussing it with a MI6 agent in London.
Lloyd takes Dylan back to his hospital room. Dylan asks if it's going to be Halloween again the next day and then thanks his father for coming to get him.
Mark and Olivia sit separately in their house.
Demetri goes over the information on Rutherford.
Stan watches over a sleeping Janis.
Charlie and Dylan go to sleep.
When Lloyd goes out to his car, Simon jokingly surprises him from the backseat. He says that the others are worried about Lloyd since he went to Los Angeles and refuses to return their calls. Lloyd tells Simon that he doesn't want to be associated with any of them, but Simon insists that they have to talk. Lloyd informs him that their experiment killed 20 million people and there's nothing to talk about.