Count Almaviva arrives in Seville to court Dr Bartolo’s ward Rosina. He pretends to be a student, Lindoro, because he wants her to fall in love with him, not his title. He is assisted in his challenging task by the town’s best barber, Figaro, whose strategy favours disguise. Bartolo is wary of the Count because he, Bartolo, is not stupid, just suspicious. He is assisted in his strivings by Rosina’s music teacher, Basilio, whose secret weapon is gossip and generating scandal.
The Count forces his way into Bartolo’s house by pretending to be a drunken soldier. The plot is about to succeed when along comes a real soldier, or rather a whole bunch of soldiers. For a moment it looks as if things are about to go horribly wrong for Lindoro, but he is neither a poor student nor a drunken soldier; he is a nobleman, and therefore above discipline in a class society. Act I ends with a terrible headache and giddiness from which all suffer as they sing together.
After the interval, the Count once again forces his way into Bartolo’s house, this time pretending to deputise for the allegedly indisposed music teacher. Since this is a comedy, the events are confused by a letter passed between Rosina and Lindoro but intercepted by Bartolo, giving rise to a host of misunderstandings. In the end, Bartolo invites a Notary, and Basilio as witness, to join him that evening so that he may be hastily wed to Rosina before the Count has time to spoil the plan.
The orchestra whips up a storm that depicts the passing of time. It is thus now evening. The Count and Figaro climb a ladder to get into Rosina’s room and are obliged to reveal that Lindoro is in fact Count Almaviva. The poor orphan Rosina takes this unexpected turn of events with admirable equanimity. But her abduction fails because Bartolo has removed the ladder from under the window. The Count, Rosina and Figaro nevertheless get to the wedding before Bartolo, sign the marriage certificate and bribe Basilio into being the second witness. When Bartolo enters, he has no option but to congratulate the happy couple and join in a jolly ode to love.