Iolanthe is a fairy of the Arcadian forest, guilty of the most serious crime of marrying a mortal man. She, on the command of the queen of the Fairies, has left her husband without explanation, but this temporary union nevertheless has resulted in the birth of Strephon, a shepherd who is mortal from the waist down and a fairy from the waist up. Strephon's love for Phyllis, a ward of Chancery, has enraged the entire House of Lords, all of whom wish to marry her themselves. Iolanthe and the fairies do their best to assist Strephon in his romantic pursuits, while the Peers do their best to thwart them. When the Lord Chancellor insults the Queen of the Fairies through a comical misunderstanding, the Queen summons her magical powers and plans revenge; an all-out confrontation occurs between the fairy forces and the Peers of Parliament, with hilarious results.