NEW YORK (CBSNewYork) — An epidemic of violence and an arsenal of guns, knives and other weapons in city schools has finally prompted Mayor Bill de Blasio to take action.

CBS2 cameras were exclusively on hand at one school Monday, where a cache of weapons was confiscated, Marcia Kramer reported.

READ MOREParents Demand Action After 5 Guns Confiscated At NYC Schools In 2 Days

The head of the school safety union is calling the mayor’s new plan “Back to the Future,” because it involves redeploying cops who, before the whole “defund the police” movement, were an integral party of reducing school violence and keeping kids safe.

And since the defund movement made safety agents in schools a political hot potato, our cameras weren’t exactly welcome at one unannounced screening Monday.

They showed up at the crack of dawn for an unannounced screening at Susan Wagner High School on Staten Island. Exclusive video shows at least a dozen agents sent from the four other boroughs with special screening equipment that is one of the centerpieces of the mayor’s new plan to crack down on school violence.

The Susan Wagner location was selected after there was a wild brawl at the school last Friday. A safety agent was dragged to the floor while trying to stop a 13-year-old who was later arrested after she allegedly used a kitchen knife to menace other students.

READ MOREString Of Violence On NYC School Campuses, Dramatic Drop In Safety Officers Has Parents Concerned For Students’ Wellbeing

And while school officials were not pleased to have the massive policing action caught on tape, they were probably thrilled with the outcome. Sources told CBS2 that brass knuckles, pepper spray and a knife were confiscated.

Another unannounced action at the Mott Haven School Complex in the Bronx, where a fully loaded .22-caliber pistol was found last week, turned up a steak knife and two box cutters, sources said.

“If we have to tap into some of our local precincts that just have that exterior presence outside, we’ll do that. But one thing I will reassure you, Marcia, and the rest of the residents of New York City, students’ safety is NYPD’s number one priority,” Chief of Department Rodney Harrison said.

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The new plan involves augmenting the depleted ranks of safety agents. The union says it’s down to about 1,500, with NYPD neighborhood coordination officers and youth community officers. It will also involve the unannounced screenings and using cops to set up 20 safe corridors from transit hubs to schools.

“This is ‘Back to the Future.’  What do I mean by Back to the Future? Last year, before the whole defund the police movement, police officers were working hand in hand with school safety agents,” said Gregory Floyd, president of Teamsters Local 237.

Floyd charges the changes are just cosmetic to make parents think things will get better, that finding guns and violent incidents, like the knife seen on video in a teen’s hand at Harry S. Truman High School, will be a thing of the past.

He’s not even happy with a promise to hire 250 more safety agents.

“Well, let’s see. We’re missing 1,500. They’re going to hire 250. So if he hired another 1,250, we’d be up to full staff,” Floyd said.

The mayor didn’t answer Kramer’s question when she asked if there needed to be more full-time scanners, and the Department of Education wouldn’t tell her how many schools even have them. The union said there are 88 schools with permanent scanners. There are 520 high schools in the city.

Marcia Kramer