Gabriella Demczuk for TIME The pizza joint is a few hundred yards away from the school where 17 of their peers and teachers were murdered a month ago. Corin had just delivered carnations to the building to raise funds for junior prom; she had handed one flower to a girl who was shot minutes later. After the fire alarm went off during his AP environmental science class, Hogg took a video of students crouching inside a tiny classroom to hide from the shooter. The video went viral, landing him a recurring spot on the cable-TV circuit. The next day, Kasky invited Wind and Corin over to his house to plan a march for gun reform. Together, they started the NeverAgain hashtag on Twitter.