A new ad has caught some attention lately for its jarring message behind a seemingly innocuous high school romance. If you’re not a fan of spoilers, watch the ad below before reading on.

To call it eye-opening would be an understatement. Like an optical illusion, once you see it for what it really is, there’s no going back to your original viewpoint. If the disorienting ending and replay of crucial scenes recalibrated the way you think about the modern high school experience, then Sandy Hook Promise, the nonprofit behind the ad, has achieved its purpose.

Organized by family members who lost loved ones to the Sandy Hook Elementary School shooting nearly four years ago, the nonpartisan group hopes to spread awareness with this public service announcement about the early warning signs we often fail to see or dismiss. Sandy Hook Promise co-founder and managing director Nicole Hockley lost her six-year-old son in the Sandy Hook massacre and aims to educate people over the course of the organization’s “Know the Signs” campaign. In an interview with Adweek, she said, “When you don’t know what to look for, or can’t recognize what you are seeing, it can be easy to miss warning signs or dismiss them as unimportant. That can lead to tragic consequences.”

Not sure what kind of behavioral red flags be mindful of? According to Sandy Hook Promise, there are a few warning signs that, when combined and observed over a period of time, can signal someone might be considering violence or self-harm. For instance, an intense obsession with firearms combined with aggressive behavior, lack of control, or sudden changes in academic performance should be cause for concern. Extreme isolation from peers can exacerbate an underlying problem, as can mental illness. Of course, explicit threats of violence—whether seen in person or via social media—should never be ignored, since the majority of shooters tell someone beforehand.

Being aware of early indicators has never been more important, considering that 186 school shootings took place between the 2012 Sandy Hook massacre and this past June. Averaged out, that’s nearly one shooting per week. Until American legislators catch up with the rest of the world on gun control, we have to take it upon ourselves to prevent horrific acts of violence.