JFK assassination drama 'Parkland' aims to spotlight new details ahead of the 50th anniversary

While much has been said, speculated, written and reported when it comes to the assassination of President John F. Kennedy, the writer/director of the upcoming drama “Parkland,” Peter Landesman, promises that almost 50 years later there’s still a lot left to learn.

“There is almost nothing about ‘Parkland’ that will feel familiar or known. It turns our preconceptions about the JFK assassination on their head, precisely because the movie is authentic and shocking in its emotional truth,” he told FOX411. “It takes an American myth we thought we knew everything about, and shows us we really knew little or nothing. The biggest surprise will be how emotional it is. How it will make you feel as if you are experiencing the power and chaos and fear of the assassination as if it is happening now, to you.”

“Parkland,” which stars Zac Efron, Colin Hanks, Marcia Gay Harden, Billy Bob Thornton and Jacki Weaver, stitches together the points of view of a handful of so-called “ordinary individuals” suddenly thrust into extraordinary circumstances after JFK was shot. The drama sheds light on the young doctors and nurses at Parkland Hospital, a Dallas chief of the Secret Service, a shocked cameraman who happened to capture one of the most watched moment’s in history, the FBI agents, the brother of the killer Lee Harvey Oswald, and Americans privy to both the assassination and Vice President Lyndon Johnson’s sudden rise to the Commander-in-Chief role.

And according to Landesman, the stories of these average citizens are crucial to understanding that moment in American history.

“The real power and truth of the JFK assassination has been buried under the murder mystery,” he explained. “‘Parkland’ doesn’t pick a fight with that speculation, as much as show you that is not important to the experience. What is bigger, and deeper, are the stories of those to whom it happened; the doctor who lost his patient, the wife whose husband died in her arms.”

And the Secret Service agent whose life changed before his eyes.

An exclusive clip obtained by FOX411 shows the trauma experienced by the Secret Service in the immediate aftermath of that fateful November 22, 1963 day in Dallas, Texas. With blood-stained shirts, the servicemen scurry to polish off a coffin and slowly place a cross on its lid – the realization of their own failures sinking in as one utters: “the first time Secret Service has lost a president…”

“We as a culture are obsessed by conspiracy and mythology,” Landesman added. “While the bigger story has been right in front of us all this time.”

“Parkland” opens in theaters October 4.