One of the teenagers hid behind a desk while a gunman shot four students inside a classroom at Florida’s Marjory Stoneman Douglas High School. Her friend, who was in another building at the school, huddled in a closet for more than two hours. A third teenager’s brother was killed in Chicago two years ago, shot nine times after getting caught in crossfire after walking his girlfriend to a bus stop.

Three students whose lives have been forever altered by gun violence are telling their stories in a short documentary produced by the gun-control group Giffords. It tells the students’ stories, following them in Washington for the March for Our Lives earlier this year. It ends with the words “Voting is our most powerful weapon,” a reference to an initiative — announced last month by Giffords, Everytown for Gun Safety and NextGen America, a liberal advocacy group founded by hedge fund billionaire Tom Steyer — that aims to get 50,000 teenagers registered to vote ahead of the midterm elections in November.

The three students in the documentary, Ke’Shon Newman, Olivia Wesch and Kayla Schaefer, each participated because they said they want people to know the realities of living through a school shooting or on the South Side of Chicago. They want to put a stop to the violence.

“A lot of people don’t really realize that kids my age have to go through so much and we worry, most people worry every day, about what’s going to happen,” Wesch said in an interview. “For somebody so young to have to worry about it ... isn’t right.”

Wesch hid in a closet for more than two hours during the Feb. 14 school shooting in Parkland, Fla., which left 17 people dead. Schaefer woke up that morning to a surprise — her parents decorated her kitchen table for both Valentine’s Day and her birthday. She was in an AP psychology class when the gunman started firing; she and her classmates dropped and ran to the other side of the classroom.

The gunman soon shot through the glass of her classroom door, hitting four students.

“I heard their cries and wheezing. There were people crying, there were people calling their moms and some people were shushing the victims who were shot,” Schaefer said. She texted her mother: “I’m scared mom.”

Most people, she said in an interview, “don’t know how truly cruel it was and how horrible it was to experience.”

Newman’s brother Randall was 16 when he was shot nine times on a Chicago street. His mother ran to the scene and saw her son dead in a pool of blood. Ke’Shon Newman was 13 at the time.

“We don’t want this to be our lives,” Newman said in an interview. “I’m strong enough to fight so nobody else has to tell another story like that.”

Newman said people have become normalized to violence in Chicago, and he wants the violence to stop and people to no longer be afraid to walk down the street or take their children to the park.

Alex King, right, and D'Angelo McDade, both graduating seniors at North Lawndale College Prep High School in Chicago, at the March for Our Lives rally in Washington on March 24. Both have been affected by gun violence: King lost a 16-year-old nephew last year and McDade was shot in the leg. (Andrew Harnik/AP)

Newman said the schools do not have enough counselors to work with students who have been affected by violence. He has always gone to schools with metal detectors — they were even in his elementary school — and said their mere presence affects young children.

“That’s not a thing a little kid should go through ― wake up every day, go through a metal detector, like you’re in a prison,” he said.

He plans to continue to stay active both to make Chicago safer and to honor his brother’s memory.

“If I can stop this, his death won’t be in vain,” he said of Randall. “They won’t have to mark him just another name, just another number.”