Upon hearing Miss Prism’s name, Lady Bracknell immediately inquires about her, insisting that she be sent for. At the same moment, Miss Prism enters, sees Lady Bracknell, and begins to show a great deal of anxiety and fear. In a sharp tone, Lady Bracknell demands to know the whereabouts of a baby boy Miss Prism lost 28 years ago.
Lady Bracknell puts the usually impervious Miss Prism ill at ease, suggesting that she is not as perfect as she seems. Lady Bracknell’s damning accusation threatens to destroy Miss Prism’s pristine reputation, overturning Algernon’s presumption that the servant classes should be pillars of moral uprightness.
Lady Bracknell proceeds to relay the details of the child’s disappearance. Departing from Grosvenor Square, Miss Prism took the baby boy out in a stroller, but never returned with the child. The pram was found three weeks later in Bayswater containing no trace of the baby, but a three-volume-novel. Overwhelmed by incriminating evidence, Miss Prism confesses that she does not know what happened to the baby. She explains that she left the house that day with the baby in the stroller and the manuscript for her three-volume-novel in a handbag. She conjectures that in a moment of absentmindedness she put the manuscript in the stroller and the baby in the handbag.
Miss Prism’s carefully crafted appearance of moral perfection is actually a lie. While making moralistic pronouncements on others, she has been hiding a dark and embarrassing secret that undermines her self-righteous façade. Miss Prism’s past reveals her hypocrisy as well as her folly. As a writer with her head in the clouds she makes the silly, yet grave error of mistaking a manuscript for a baby, showing that she is just as susceptible to the lure of fantasy as her pupil Cecily.
Upon hearing this detail, Jack feverishly asks Miss Prism about where she left the handbag. Whimpering, she admits to having left it in a coatroom at Victoria station on the Brighton line. Excited, Jack rushes out of the room and returns onstage with the handbag, asking Miss Prism is she can identify it as the handbag she misplaced. She looks it over carefully and confirms that it is hers, delighted that it is back in her possession. Having pieced together the mysterious disappearance of the baby boy, Jack declares that he is the lost boy who was abandoned in Miss Prism’s handbag and embraces her as his mother.
Through this story, Wilde unites Miss Prism’s absentmindedness as a fiction writer with the backstory behind Jack’s fictional life. While the handbag and coatroom have come to represent blanks in Jack’s personal history, they are now filled with a colorful story, created because of Miss Prism’s focus on fiction rather than the duties at hand. Wilde underlines the absurd nature of reality by highlighting Miss Prism’s delight at retrieving her handbag over finally finding the child she lost.
Miss Prism recoils, reminding Jack that she is unmarried. Jack misconstrues her point, launching into a speech about forgiveness and redemption that criticizes society’s double standards for men and women. But Miss Prism suggests that Jack should look to Lady Bracknell for the truth about his identity.
With Jack’s speech, Wilde makes a pointed statement about the unequal treatment of men and women. Jack seems progressive in forgiving a “fallen woman” (i.e. one who he thinks gave birth without being married), while thinking his own duplicitous actions require no forgiving at all.
Without fanfare, Lady Bracknell explains that Jack is the son of her poor dead sister, Mrs. Moncrief, which also makes him Algernon’s older brother, but also Lady Bracknell’s nephew, and Gwendolen’s first cousin. Jack’s newfound family relations overturns Lady Bracknell’s prohibition against his marriage to Gwendolen. Jack joyfully announces that he does indeed have a brother!
Jack’s discovery of his family line breaks down one barrier against his marrying Gwendolen. (Cousin marriage was acceptable in Victorian England). By gaining a mother and brother, he gains the relations he was lacking before, making Jack’s visions of family a reality.
But the mystery of Jack’s true name remains, as his present name remains an “irrevocable” obstacle to Gwendolen’s consent. Lady Bracknell believes that Jack, as the first born son, is likely named after his father, General Moncrief, but she, nor Algernon can remember his full name. Jack rushes to his bookshelves, which house volumes of Army Lists from the last forty years. Jack feverishly flips through the books’ long lists of “ghastly names”, until he finds General Moncrieff’s first name: “Ernest John.”
Wilde makes fun of the union between class and character by making Jack’s marriageability contingent upon his name, as well as family background. Jack’s relations satisfy Lady Bracknell’s criteria, but they are not enough for Gwendolen, who wants him to be “Ernest.” That Jack has to prove his “Ernestness”/ earnestness by verifying his name from a list of “ghastly names” is absurd, and highlights the general absurdity of the importance of names and family lines in Victorian decisions about love and marriage.
Jack realizes that he has been telling the truth the entire time: his name is in fact Ernest, but also John, and he does have a troublesome younger brother, Algernon. Jack turns to Gwendolen and asks if she will forgive him for telling the truth. She does, declaring him “my own!” Each couple—Jack and Gwendolen, Miss Prism and Dr. Chasuble, and Cecily and Algernon—embrace “at last,” while Jack declares to Lady Bracknell that he has learned the “vital Importance of Being Earnest.”
The marriage chase concludes when Gwendolen asserts her hold on Jack by claiming him as her “own.” Meanwhile, the verification of Jack’s lies with concrete proof of their legitimacy makes his fictional life a bonafide reality. By pretending to be “Ernest,” Jack’s art of deception has actually become “earnest,” or a sincere depiction of his real life as it is. His life is art; his art is life.