It appears to tell a simple story from an American high school, but also has a hidden meaning revealed at the end.
The unexpected message has propelled the short film to more than two and a half million views on YouTube in just three days.
Spoilers follow below - you may want to watch the video to the end first.
It was created by the Sandy Hook Promise group, set up by family members of the victims of the Sandy Hook school shooting.
On December 14, 2012, 20 children and six adults were killed at Sandy Hook Elementary School by 20-year-old Adam Lanza, who had killed his own mother earlier that morning. He was a former student of the school.
"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," said Nicole Hockley from Sandy Hook Promise, whose son Dylan died in the shooting.
"Everyone has the power to intervene and get help. These actions can save lives."
In the aftermath of the 2012 shooting, Barack Obama called for action on gun control, despite the political difficulties.
But three years later, he called gun control the greatest frustration of his presidency, as the US Congress repeatedly blocked moves to tighten restrictions.
The gun control movement reached a peak in the summer when more than 200 Democratic politicians staged a sit-in at the House of Representatives to demand a vote on restricting firearm purchases, in the wake of the Pulse nightclub shooting in Florida.
The Gun Violence Archive non-profit organisation maintains a "mass shooting tracker" of attacks where four or more people were shot in a single incident.
It estimates that so far in 2016, 425 people have been killed in 362 mass shootings in the United States. It says there were 333 mass shootings last year, and 275 two years ago.
The new President-elect Donald Trump, however, frequently expressed support for the second amendment - the right to bear arms - during his campaign, saying his rival Hilary Clinton wanted to abolish it.
On one occasion, he caused a significant controversy when he suggested gun rights supporters could somehow stop Ms Clinton's campaign.
In May, the National Rifle Association, a pro-gun lobby, endorsed Mr Trump for president.

The Land and Lakes plans were agreed after a £20m deal to mitigate the impact of the development on Holyhead.
It will see a leisure park with 500 lodges and cottages at Penrhos Coastal Park, a further 315 lodges at Cae Glas, and 320 homes in the Kingsland area.
Some of the new accommodation will house workers if a new Wylfa nuclear power plant is built on the island.
"This was the largest planning application ever to be considered by the Isle of Anglesey county council," said chief executive Gwynne Jones.
"The terms agreed with Land and Lakes will bring in excess of £20m to mitigate the possible impacts an application of this scale will have on the area.
"Importantly, environmental concerns raised will also be addressed and will be the subject of appropriate remediation."
The original application for the Land and Lakes development was first put forward in 2011, following the closure of the giant Anglesey Aluminium plant in the town.
Controversially, the first part of the plans will see a holiday village built on part of the Penrhos Coastal Park, which was owned by the former metal plant.
The planning proposals were initially agreed in 2013, but it has taken since then to thrash out the deal on what is known as a 106 agreement.
It makes developers pay back into a community to cover the costs of providing additional school places, doctors and council support services.
It also ensures the bill for any additional environmental work is picked up by the developers.
The island's head of economic regeneration, Dylan J Williams added: "We're hopeful that the Land and Lakes project will bring long term economic benefits for the island as a whole and will represent a positive step in the sustainable transformation of our economy.
"We now look forward to working with Land and Lakes to ensure people and businesses can take advantage."
A video telling the story of two schoolchildren forming a friendship - with a twist - has gone viral online.
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A £120m holiday village and houses on Anglesey which could bring about 600 jobs has been given the final go-ahead.