John Adams has a new opera ready for its U.S. premiere, and careful listeners will note a distinctly un-Adams-like influence lurking behind the score. “The libretto, which Adams crafted with his longtime collaborator Peter Sellars, is based on an American Indian folk legend. But the original impetus behind the work, Adams says, is ‘The Magic Flute,’ that miraculous blend of subtle craftsmanship and pop accessibility that Mozart wrote just months before he died.”