When iconic film producer Frank Marshall discovered a never-before-seen collection of Frank Sinatra recordings and material at his daughter Tina’s house, he immediately got to work turning his findings into HBO’s upcoming two-night, four-hour documentary Sinatra: All or Nothing at All. Directed by Oscar winner Alex Gibney and created with cooperation from Sinatra’s family, the documentary aims to paint a “good portrait of the man in terms of his life and times.”

Work on the highly-anticipated HBO documentary began after Marshall saw a number of film boxes stacked in a bedroom in Tina Sinatra’s home, a discovery which he equates to finding the Ark of the Covenant, a reference to Indiana Jones: Raiders of the Lost Ark, which he produced.

“We opened the door and this glow came out of the room. I slowly opened one of the boxes, hoping that it wasn’t dust. And when I looked inside, there it was, pristine, well-preserved, 16-millimeter film,” said Marshall.

The producer’s favorite finding was a 1971 Los Angeles performance Sinatra initially planned to be his “retirement” concert. Gibney told USA Today that the performance acts as the backbone of the documentary, and the 11 songs in the concert “serve an important narrative function” in the film.

“It was this magnificent footage, not shot in a traditional, glitzy way that you would normally do for a TV special. Frankly, that’s its charm and power. There’s an intimacy and authenticity in it and also a bit of amateurishness,” said Gibney. “Sinatra never wrote an autobiography, so it was my interpretation that this retirement concert was, up to that moment in time, his way of telling his own story in song.”

Viewers can expect the film to cover the many highs of Sinatra’s life and career, including his rise to fame and his Oscar-winning movie career. While Sinatra: All or Nothing at All is intended to be a “birthday celebration” to honor the 100 years since his birth rather than an investigative film, some portions of the documentary will also highlight the singer’s “rough and tumble” and occasionally “cruel” nature. Gibney promises to reveal some new details about Sinatra’s relationships with dangerous mobsters, and discuss how he sent a lawyer to end his relationship with Mia Farrow. Sinatra’s first wife Nancy and the couple’s children, Nancy, Frank Jr. and Tina, provided never-before-seen early photographs and recordings of the singer talking about his life for use in the documentary.