 Mengone (tenor), the apothecary s apprentice, loves Grilletta (soprano), but Volpino, a man-about-town, loves her too. Sempronio, Grilletta s foster father, seems unlikely to allow them to marry, as he is interested in her himself. Calling Mengone s bluff to see if he really loves her, Grilletta pretends to accept Sempronio (tenor), but the notary who arrives to marry them is actually Volponio in disguise. Mengone also appears, also disguised as a notary!