By Sunday, only four days after the school shooting at Marjory Stoneman Douglas High School, in Parkland, Florida, the activist movement that emerged in its aftermath had a name (Never Again), a policy goal (stricter background checks for gun buyers), and a plan for a nationwide protest (a March for Our Lives, scheduled for March 24th). It also had a panel of luminary teens who were reminding America that the shooting was not a freak accident or a natural disaster but the result of actual human decisions.

The funerals continued in Parkland and surrounding cities—for the students Jaime Guttenberg and Joaquin Oliver and Alex Schachter and the geography teacher Scott Beigel—with attendance sometimes surpassing a thousand people. On a local level, at least, the activism did not overshadow the grieving. The tragedy affected this student body of more than three thousand people in different ways: some students lost their closest friends, others hallway acquaintances. And the student leaders knew, with the clarity of thought that had distinguished them from the beginning, that the headline-industrial complex granted only a very narrow window of attention. Had they waited even a week to start advocating for change, the reporters would have gone home.

Also, different people express grief in different ways. The activists are grieving, too, but it’s not a coincidence that a disproportionate number of the Never Again leaders are dedicated members of the drama club. Cameron Kasky is a theatre kid. Before he went on Anderson Cooper, he was best known as a class clown. “I’m a talker,” he told me. “The only thing I’ve had this whole time is the fact that I never shut up.” Kasky started writing Facebook posts in the car after he and his brother, who has special needs, were picked up after the shooting by their dad. “I’m safe,” he wrote in the first, posted two hours after the shooting. “Thank you to all the second amendment warriors who protected me.” For the rest of the day, in between posts about missing students and recalling the experience of hiding in a classroom with his brother, Kasky’s frustration grew: “Can’t sleep. Thinking about so many things. So angry that I’m not scared or nervous anymore . . . I’m just angry,” he wrote. “I just want people to understand what happened and understand that doing nothing will lead to nothing. Who’d have thought that concept was so difficult to grasp?”

The social-media posts led to an invitation from CNN to write an op-ed, which led to televised interviews in the course of the day. “People are listening and people care,” Kasky wrote. “They’re reporting the right things.” That night, Thursday, after the candlelight vigil ended, Kasky invited a few friends over to his house to try to start a movement. “Working on a central space that isn’t just my personal page for all of us to come together and change this,” he posted. “Stay alert. #NeverAgain.” He had thought of the name, he later told me, “while sitting on the toilet in my Ghostbuster pajamas.” In early interviews Kasky had criticized the Republican Party, but he and his friends had decided since that the movement should be nonpartisan. Surely everyone—gun owner or pacifist, conservative or liberal—could agree that school massacres should be stopped. The group stayed up all night creating social-media accounts and trying to figure out what needed to be said, “because the important thing here wasn’t talking about gore,” Kasky said on Sunday. “It was talking about change and it was talking about remembrance.” It was then that they decided to petition for more thorough background checks. As Alfonso Calderon, a co-founder of Never Again, who was there that night, told me, “Nikolas Cruz, the shooter at my school, was reported to the police thirty-nine times.” He added, “We have to vote people out who have been paid for by the N.R.A. They’re allowing this to happen. They’re making it easier for people like Nick Cruz to acquire an AR-15.”

Further Reading New Yorker writers respond to the Parkland school shooting.

They launched their new Facebook page just before midnight on February 15th. “Thank you to everybody who has been so supportive of our community and please remember to keep the memory of those beloved people we’ve lost fresh in your minds,” Kasky wrote.

While Kasky, Calderon, and their other friends huddled among snack wrappers in a gated-community war room, another student was developing a different plan. Jaclyn Corin is the seventeen-year-old junior-class president at Marjory Stoneman Douglas. She woke up the morning after the attack to the confirmation that her missing friend, Joaquin Oliver, was among the dead. She cried so hard that her parents had to hold her down. She also started posting on social media. “PLEASE contact your local and state representatives, as we must have stricter gun laws IMMEDIATELY,” she wrote on Instagram. It was after she went to grief counselling, and after the candlelight vigil that evening, that Corin first talked to the Democratic Florida congresswoman Debbie Wasserman Schultz. Conversations with state representatives followed, and preliminary arrangements were made to bus a hundred Douglas students and fifteen chaperones to Tallahassee to address the state legislature. Yesterday, I asked Corin if she had been politically active before the shooting. “Not even a little bit,” she said. “It’s so personal now. I would feel, like, horrible if I didn’t do anything about it, and my coping mechanism is to distract myself with work and helping people.” Corin was also prepared to advocate for gun-law reform, having worked on a fifty-page project about gun control for her A.P. composition-and-rhetoric class a couple of months before. “We have grown up with this problem,” she said, when I asked how the students had been so ready to argue the issue. “We knew this stuff. It’s not like a new, fresh horrible thing that’s happening, it’s been preëxisting even before we entered the world.”

By Friday, Corin had accepted an invitation from Kasky to join forces under Never Again. By Saturday, other students who had been independently talking to the media about gun control had joined, too—names that are now becoming familiar to the American public: David Hogg, the reporter for the school paper who appeared on national news broadcasts the morning after the shooting demanding action from elected officials; Sarah Chadwick, whose profanity-laced tweet criticizing Trump went viral soon after the shooting; and Emma (“We Call B.S.”) González, whose speech became the defining moment of a gun-control rally in Fort Lauderdale on Saturday. González, a senior, gave her first CNN interview on the night of the vigil. The invitation to speak at the rally had followed, and she wrote her speech the day she gave it. She had not anticipated how widely it would be shared. (Her last experience of activism, she told me, had been last year’s underwhelming March for Science.) She had simply written down the thoughts she had been sharing with her friends. “This is how I’m dealing with my grief,” she said. “The thing that caused me grief, the thing that had no right to cause me grief, the thing that had no right to happen in the first place, I have to do something actively to prevent it from happening to somebody else.” Kasky recruited Hogg and González for Never Again at the rally, where he also spoke.

“We said, ‘We are the three voices of this.’ We’re strong, but together we’re unstoppable,” Kasky said. “Because David has an amazing composure, he’s incredibly politically intelligent; I have a little bit of composure; and Emma, beautifully, has no composure, because she’s not trying to hide anything from anybody.” “All these kids are drama kids, and I’m a dramatic kid, so it really meshes well,” González added.

Following the Fort Lauderdale rally, after more media interviews, Kasky invited everyone over for a slumber party. “We were just saying, ‘O.K., look, we need to have preparation and beauty sleep,’ ” he said. There was very little sleep.