The Abbey, a venue of the Ottawa Arts Center, will screen “Nasty — The Battle After the Mission,” a documentary about Lt. Col. Daniel Nash, USAF, on the 25th anniversary of 9/11.

Nash was among the first responders scrambled from Otis Air Force Base on the morning of Sept. 11, 2001. He and his commander were chasing the first hijacked plane when he witnessed the second plane strike the South Tower from about 60 miles away. He spent the next six hours circling over Manhattan, protecting U.S. airspace.

The documentary, released this May, explores Nash’s role that morning and his subsequent struggle with PTSD, which affected him for the rest of his life. It is the third public screening since its release.

Director John Scaletta, a high school friend of Nash’s, filmed and researched the project with what Brendan Nash, Daniel’s brother and an Ottawa resident, calls “an elegant and powerful touch.” The film has won four awards at film festivals.

Brendan Nash said the screening is an opportunity to raise awareness about the invisible wounds many military veterans carry.

Scaletta will attend the screening and participate in an on-stage interview hosted by John Williams of WGN radio following the film.

More information is available at ottawacenter.org.