Act I
In Florodora, a small island in the Philippines, the popular fragrance "Florodora" is manufactured from the essence of the Florodora flower. The perfume factory, along with the island itself, is owned by Cyrus W. Gilfain, an American who finagled the business away from Dolores' family and is now the island’s reigning sovereign and sole employer. Although Dolores is now forced to work for Gilfain, she remains optimistic. Frank Abercoed, who is really Lord Abercoed in disguise, has arrived on the island to act as Gilfain's manager. He is immediately smitten with Dolores, and she with him.
Aboard a ship docked at the Florodora harbor are Lady Holyrood, titled but penniless, who has come to Florodora at Gilfain's suggestion to find a husband – specifically, Frank. She is accompanied by Gilfain, his daughter Angela, who is betrothed to Captain Arthur Donegal, Lady Holyrood's brother, and several of Angela's friends (the "English Girls"), who intrigue Gilfain's clerks. Also aboard the ship is Anthony Tweedlepunch, a detective who is searching for the girl who rightfully owns the perfume business. He comes to the island disguised as a traveling showman, phrenologist, hypnotist, and palmist.
Gilfain discovers that Frank and Dolores have fallen in love. In an effort to thwart Dolores' rightful claim to the Florodora fortune, Gilfain plans to marry her himself. He hires Tweedlepunch, who he thinks is an actor, to break up the love affair between Dolores and Frank, thereby making Frank available to marry Angela. By presenting Tweedlepunch as a highly respected phrenologist, Gilfain plots to marry off his clerks to the heads of the Florodora farms (all young island girls), thereby attaining even more control of the island. Tweedlepunch plays along, duly examining everyone's cranial bumps of love to pronounce the proper marriage couples.
Frank refuses to marry Angela, and Gilfain discharges him. Gilfain, based on the fraudulent pronouncements of Tweedlepunch, has decreed that the clerks will wed the island girls or be discharged. Everyone is upset. Frank must now return to England, and he tells Dolores he must go but will return for her if she waits patiently. Everyone meets at the dock to see Frank off.
Act II
Six months later, Gilfain has managed to become the owner of Abercoed Castle, Frank's ancestral home in Wales, and everyone has travelled there. Gilfain's clerks, having been discharged rather than marry the island girls, finally meet up with their English girls (Angela's friends). Tweedlepunch has finally realized that Dolores is the rightful heir to the Florodora fortune. He tells her that her father was his only friend, and that he will help her retrieve her family business. They break into the Abercoed castle but are surprised by a chorus of lords and ladies who demand to know who they are. In desperation they try to convince everyone that they are the evening’s entertainment.
Lady Holyrood, with no prospective husbands in sight, decides that Gilfain will become her next husband. Frank, who has been refused entrance to the castle by Gilfain, defies orders and maneuvers his way inside the courtyard. There he sees Dolores for the first time since he left the island. After some confusion, Frank tells Dolores that he is really Lord Abercoed and was unable to return to her in Florodora because he was trying to keep Gilfain from acquiring his ancestral home. Tweedlepunch finally confronts Gilfain and spins a wild ghost yarn that terrifies Gilfain into admitting that he has stolen the perfume business. Gilfain returns the properties he has taken from Dolores and Frank. Frank marries Dolores; Gilfain marries Lady Holyrood; and Angela, marries Captain Donegal.