The manuscript shows the play in an early stage of its development; it is in the hand of a professional scribe, but contains corrections and additions in Shirley's handwriting. The MS. "contains scenes and portions of scenes" not in the 1653 printed text; "there are several characters...that were afterwards dropped." The MS. also shows signs of preparation for production, so that it is uncertain which version of the play, the MS. or the printed text, was acted onstage in 1664. Synopsis A Spanish nobleman named Piraquo was banished from Spain in his youth; after a very profitable career as a pirate and a stay at the royal court of Portugal, his banishment has been lifted by Don Carlo, the heir to the Spanish throne. Piraquo's son Don Manuel is a close friend to Don Carlo, and returns to Spain with his father. Don Manuel quickly falls in love with Clara, the daughter of Duke Mendoza. Clara loves him in return and agrees to marry him – but the Spanish princess, Maria, also falls for Manuel, even though she is betrothed to marry Prince Antonio of Portugal. Don Carlo is also engaged to a Portuguese princess, Isabella – though Carlo too is in love with Clara. Carlo's and Maria's father, the King of Spain, is unhappy about all of this. The King's brother, Roderigo, informs Prince Antonio that Carlo courts Clara instead of Maria; he provokes Carlo's anger at the idea that Manuel is courting Maria. The fact that this is not strictly true does not bother Roderigo; the play's Machiavellian stage villain, he creates as much trouble as he can. Yet another complication arises: Pedro, who is both a kinsman to Piraquo and Manuel and a servant to Duke Mendoza, knows a secret — the "court secret" of the title, which somehow involves Duke Mendoza and a mysterious treasure, and Carlo and Manuel too. The jealous Prince Antonio meanwhile provokes a duel with Manuel, which leads to Manuel's imprisonment. A meeting between Clara and Princess Maria shows them that they are rivals for Manuel's love; similarly Carlo and Manuel learn that they are rivals for Clara. Don Carlo gains Manuel's release and reconciles him with Prince Antonio; Manuel responds by releasing Clara from their marriage contract and letting her choose for herself — though Clara once again chooses Manuel. Carlo, stung by her rejection, challenges Manuel to a duel; Clara