Act I
A barber named Figaro meets with an old employer named Count Almaviva. The Count is in love with a girl named Rosine, who is under the guardianship of a doctor named Bartholo.
Rosine secretly gives the Count - disguised as a commoner - a note. The Count and Figaro strike up a plan for Rosine to elope with the Count without the knowledge of the old doctor Bartholo.
But while Figaro and the Count are planning, they overhear Bartholo discuss his wedding plans for Rosine - which are to occur the following day.
Figaro and the Count make haste to catch Rosine before Bartholo does.

Act II
Figaro gives all of the servants in the house various medicines to keep them occupied on their own states. Then he is able to go to Rosine and tell her of the Count, aka Lindor's, love as well as Bartholo's plan of marriage.
The Count, disguised as Lindor disguised as a drunken soldier, comes to the door seeking assistance. He sneaks a letter to Rosine.

The Count comes in as another disguise - an assistant to Rosine's music teacher. Bartholo goes along with it, thinking the Count/assistant is on his side. Figaro comes in to give Bartholo his shave and makes as many distractions as possible so that Rosine and the Count can have some words without distraction.

Act IV
After a revealing conversation with Rosine's music teacher, Bartholo goes to Rosine to slander the Count. Rosine innocently believes what her guardian tells her and agrees to marry Bartholo.
Bartholo decides to act quickly by getting the notary over and rounding up police and other armed persons to ward off the Count and Figaro.
Will Figaro and the Count be able to win Rosine back, or will she marry Bartholo? You will have to see the opera to find out.