A chilling new ad spot by Sandy Hook Promise depicts kids showing off their new “back to school” gear while a mass shooting suddenly erupts around them and—be warned—it’s a tough watch.

It’s the latest public service announcement from the group that was set up to help protect children from gun violence in the aftermath of the mass shooting at Sandy Hook Elementary on Dec. 14, 2012. The Connecticut massacre claimed the lives of 20 first graders and six adult staff members.

The video, titled “Back to School Essentials,” shows the kids using their new colored pencils, scissors, and socks to help them as they try to survive a school shooting that’s going on around them. It’s part of Sandy Hook Promise’s “Know the Signs” campaign that aims to warn students, teachers, and parents about the signs that someone is planning a shooting.

One student running from a shooter says: “These new sneakers are just what I needed for the new year.” Another wraps her long socks around a bleeding classmate’s leg that has been wounded by a bullet, and says: “These new socks? They can be a real lifesaver.” A third student uses his new skateboard to smash a window in a desperate attempt to escape the shooter.

The terrifying end of the video comes with a girl weeping in a bathroom stall and texting her mom that she loves her before the door creaks opens followed by the sound of approaching footsteps. “I finally got my own phone to stay in touch with my mom,” the student says.

The video, which debuted on Today this morning, concludes with the message: “It’s back to school time and you know what that means. School shootings are preventable when you know the signs.”

It’s the latest in a string of powerful PSAs from the group. Last year, it released a video from the point of view of a school shooter as everyone around him ignores the warning signs of what he’s planning. Another mimicked a local news broadcast about a shooting that’s due to happen the next day with the tagline: “You can stop tomorrow’s shooting.”

As part of its “Know the Signs” campaign, Sandy Hook Promise has published a long list of warning signs to look out for that could give an indication that someone is planning a mass shooting.

The group gives the chilling statistic that, every day, eight children die from gun violence in the U.S. and 32 more are shot and injured.