A young mother is at the laundromat with her baby, Sam, who won't stop crying. After putting Sam in the backseat, she ends a phone call and finds that Sam has disappeared. As she searches for him she sees a little boy calling out for his dad, who has also vanished. The parking lot and surrounding area erupt in mayhem, and several juxtaposed 911 calls are placed reporting the disappearance of numerous people.
Three years later
Police chief Kevin Garvey witnesses Dean shoot and kill a dog and flee in a truck during his morning run. After attempting to return the dog's remains to its owner, he rushes to a meeting with the Mayor, Lucy Warburton, to plan the Heroes Day parade for their town of Mapleton, New York. Though the Mayor is confident that it will be an uneventful gathering of grieving people, Kevin warns that the local Guilty Remnant chapter, who have grown to the point where they own several houses on a cul-de-sac in town, will protest the event, and leaves when his request to cancel the parade is denied. At a Guilty Remnant house, Laurie wakes amongst her fellow Remnants, and is angered when she is left out of the group's planned protest during the parade. As the Remnants do not speak, she writes her grievance to the group's leader, Patti, who allows her to join in. At school, Kevin's daughter, Jill chooses not to participate in prayer. After breaking another girl's nose during field hockey practice, she is invited to a party by her friend, Aimee. She gets permission from Kevin over dinner, and leaves for the party, but departs soon after a game in which Aimee and Jill's crush, Nick, have sex. While helping Adam and Scott Frost look for car keys, she finds the dead dog her father picked up inside the trunk of her car. With the help of the twins, she buries the dog. Elsewhere, Kevin's son Tom drives a blindfolded Congressman Witten to a compound outside of town. Upon their arrival, the Congressman is taken to meet Holy Wayne, and Tom chats with Christine. Once the Congressman is ready to leave, Tom is asked to stay the night, as Wayne wants to speak with him. Wayne comes to Tom at night and tells him that Christine is important, and that he needs to protect her from bad things that are coming for them. At dinner with her fiancé, Meg continues to be harassed by Guilty Remnant members, including Laurie, for unknown reasons. When the couple head home, she finds the same Remnants standing outside her home, and slaps Laurie before heading inside in tears. The following day, Kevin arrives late to the parade and marches with the rest of the town. The Mayor unveils a statue in tribute to the victims of The Sudden Departure, and invites Nora Durst, a woman who lost her husband and two children, to speak. As she finishes, the Guilty Remnants arrive holding letter signs to spell "stop wasting your breath". The assembled townspeople take offense to their protest and attack them, and Kevin and his officers try to keep the peace. That night, after getting drunk, Kevin arrives at the Guilty Remnants cul-de-sac and demands to speak with Laurie, who is revealed to be his wife. He begs her to come home but she refuses to speak with him, and he is thrown off the property. Shortly afterward, Meg arrives in a taxi and asks Patti if she can stay with their group for a few days, and Patti has Laurie take her inside. Kevin stops driving when he sees a deer standing in the middle of the road. As he exits his car to approach the deer, it is chased down, killed, and eaten by a pack of dogs. Dean, arriving soon after, tells Kevin that "they are not our dogs anymore", and the pair shoot at the pack.
The pilot episode received 1.77 million viewers when it premiered, and achieved a 0.8 rating in the 18-49 demographic. The A.V. Club gave the episode a B+. Alan Sepinwall of HitFix said of the Garvey family: "What I've always found interesting about the story is that it focuses on the Garvey family, who lost absolutely no one close to them in the Departure, but who have all lost each other as a result" and stated "I don't know how many of you are going to have the patience for this going forward, but I'm all in." For the 67th Writers Guild of America Awards, the pilot episode was nominated for Best Long Form Adapted.
