In 1826, Mozart’s operas – including the Marriage of Figaro and Don Giovanni - are being performed for the first time in New York City.  A bookseller and amateur musician is murdered, and a hand-copied section of the Figaro libretto is discovered by the body. Lorenzo Da Ponte, the aged author of the librettos for these works, has emigrated from Europe to New York City some years earlier. He is called before an inquest.

Distraught, he asks for help from his close friends, Beatrice Paradise, the intellectual madam of his favorite brothel, the Feathered Strumpet, and her major domo, Osric Primrose, a freed slave.

Some weeks later, Da Ponte presents a performance of Don Giovanni.  A singer is murdered, and a quote from the libretto is again found by the body. Da Ponte is called before another inquest. This time, he is accused of the crime and sent to the notorious Bridewell Prison awaiting an indictment. 

Taking advice in criminal investigation from the young Edgar Allen Poe, with the cooperation of Reverend Clement Moore, author of the famous poem, A Visit from Saint Nicholas, and with Osric at her side, Beatrice creates a “palace of secrets” on a recent invention – the blackboard. She and Osric use it to track clues, and eventually determine who committed the murders and why.