Synopsis

The prologue describes a strange man living in a castle above a seaside town who shuns the town's social life and the Contessa's parties and refuses to go to church on Sundays. The strange man is a poet who on three successive Sundays takes a different pet on a walk through the streets of the town. On the first Sunday, he parades his unicorn. The Contessa insists she must have a unicorn as well and persuades her husband to get one for her. The citizens of the town then buy unicorns as well.

On the next Sunday, the poet is seen with a gorgon. The Contessa and townspeople assume he has killed his unicorn and promptly kill theirs to replace them with gorgons.

On the third Sunday, he appears with a manticore. They once again follow suit by killing their gorgons and buying manticores.

When the poet fails to appear on the fourth Sunday, the townspeople assume he has killed his manticore too. Scandalized, they march to his castle to attack him. When they arrive, they find the poet dying surrounded by his three pets, all of whom are alive. In the twelfth and final madrigal he berates the townspeople for slavishly following fashion. Unlike them, he had kept all his pets: "You, not I, are the indifferent killers of the poet's dreams. How could I destroy the pain wrought children of my fancy?" The poet then bids farewell to each of his creatures in turn and tells them "Not even death I fear as in your arms I die."[11]

https://en.wikipedia.org/wiki/The_Unicorn,_the_Gorgon,_and_the_Manticore