''Parkland'' weaves together the perspectives of a handful of ordinary individuals suddenly thrust into extraordinary circumstances: the young doctors and nurses at Parkland Memorial Hospital; Dallas's chief of the United States Secret Service; Abraham Zapruder who captured what became the Zapruder film; the FBI agents who were visited by Lee Harvey Oswald before the shooting; the brother of Lee Harvey Oswald, left to deal with his shattered family; and JFK's security team, witnesses to both the president's death and Vice President Lyndon Johnson's rise to power.