A 1999 article in The New York Times was the initial inspiration. It described a maximum security prison in Florence, Colorado where these four inmates were held in solitary:

Ted Kaczynski(Bass), the Unabomber
Timothy McVeigh(Tenor), the Oklahoma City Bomber
Ramzi Yousef(Countertenor), the first and unsuccessful World Trade Center Bomber
Luis Felipe (Baritone), Head of the Latin Kings Gang,”the only one who didn’t bomb!”

For one hour all four are taken together into the prison yard, put into adjoining chain link cages and allowed to communicate, the only human contact of their day.  The New York Times called it “the oddest coffee klatsch in the history of Western Civilization.”  That hour is our opera.  And it is exactly one hour.  When the hour is up, the opera is over no matter where in the score.