Aurelio is a worthy son who has been disinherited by a capricious father, in favour of his wastrel younger brother Careless (the latter is the "fine companion" of the title).
The lovers' plans to marry are frustrated by Aurelio's lack of means; and they are separated physically by Aurelia's father, the usurer Littlegood.
Spruce is a would-be lady's man who carries a box full of pre-written love letters, only the names left blank.
In addition to Valeria there is the high-spirited Aemilia; son Lackwit is the darling of his mother, Fondling Littlegood, who encourages him to live the life of a gentleman and a gallant, much to his father's displeasure.
Littlegood wants to marry off his daughters to husbands of his choice; he plans to bestow Valeria upon Spruce, and Aemilia on the elderly Dotario, the uncle of Aurelio and Careless.
To avoid public embarrassment and keep the family secrets, Littlegood agrees to return Careless's mortgaged lands to him, and Dotario provides Aurelio with an income.
Captain Whipple is a version of the "Miles gloriosus" of classical comedy: he talks big and blusters, but is a coward at heart.