It is set in England during the Victorian era, and its primary source of humour is based upon the main character Jack's fictitious younger brother Ernest.
Warning: Wikipedia contains spoilers!
Jack's friend, Algernon, has a fictitious friend, Bunbury, through whom he is able to feign both piety and dedication - as Bunbury is in ill health, of course - while avoiding any obligations he chooses, due to his unfailing dedication to his sick friend.
He discloses the fictional friend to his real-life best friend, Jack, having discovered that the latter has only assumed the name of Ernest for his visits to the city. Jack is in fact a foundling, a fact that does not endear him to his prospective mother-in-law, the terrifying Lady Bracknell - one of the great comic characters of English literature. Her most famous is her line responding to the fact that Jack was found in a handbag - most people know the one.
Alas, unbeknownst to Algernon, Jack has announced the tragic death of Ernest, as the ruse begins to interfere with his own romantic quests.
A hilarious series of comic misunderstandings follows, as Algernon-as-Ernest visits the country (as a dead man, as far as the hosts are aware), and Jack shows up in his mourning clothes. There he encounters Jack's ward, Cecily, who believes herself in love with Ernest - the non-existent brother she has never met. The play contains many examples of Wilde's famous wit.
It has a small cast, which is as follows:
The full script online: " class="external">http://organicfamily.com/homestage/earnestScript.html The comedy has been successful even when performed in translation. The title being untranslatable, it is then usually staged under the title Bunbury -referring to deceit in general.
Movie versions