The curtain rises on an Arcadian landscape where a chorus of fairies tell of their regret that Iolanthe had been banished for over 25 years by the Fairy Queen for the heinous crime of marrying a mortal, and that although her life was spared, she has chosen to work out her punishment at the bottom of the stream to be near her son, Strephon, who is an Arcadian shepherd. The fairies entreat the Queen to forgive Iolanthe and, after reflection, she gives way to their request. Iolanthe is summoned and pardoned. Strephon enters and tells his mother and newly found aunts that he is about to marry Phyllis, a ward in chancery, despite the refusal of the Lord Chancellor to give his consent.

The Fairy Queen, favourably impressed by Strephon, promises him protection if ever he needs it. The fairies depart leaving Strephon and Phyllis to sing of their love for each other.

The peers enter and the Lord Chancellor tells them that he has sent for Phyllis, whose beauty affects them all (including himself), but she tells them that her heart is given. Much put out the Peers depart.

The Lord Chancellor tells Strephon that he still withholds his consent, so Strephon seeks out his mother and pours out his woes to her. The Peers return with Phyllis and refuse to believe that Iolanthe (who being a fairy is ageless) is strephon’s mother.

Phyllis, broken-hearted at what she believes is his infidelity, declares she will accept in marriage either Lord Tolloller or Lord Mountararat.

Strephon calls on the Fairy Queen for assistance and she punishes the Peers for their levity by declaring that she will send Strephon into Parliament with the powers which will enable him to pass every bill he wishes, including one which will throw open the Peerage to competitive examinations.

Synopsis - Act I

Act II opens with Private Willis on sentry-go in the Palace Yard, Parliament. He is meditating on life in general and politics in particular.

The Peers and fairies enter, the former in great consternation and the latter jubilant at Strephon’s success in Parliament. However, the fairies are becoming interested in the Peers for which they are rebuked by the Fairy Queen.

Mountararat and Tolloller argue over which of them shall marry Phyllis but they decide that their friendship is more important than their love for her. They ask the Lord Chancellor to make another attempt to reconsider the problem that has been a ‘Nightmare’ to him, that is to give his own consent to his own marriage to Phyllis.

Iolanthe pleads for Strephon and Phyllis and reveals she is the Lord Chancellor’s wife. She must now incur death.

The Lord Chancellor saves the day by inserting a single word “that every fairy shall die who ‘don’t’ marry a mortal” into the Fairy Law.