Light Opera Theatre of Sacramento presents Iolanthe or The Peer and the Peri, by Gilbert and Sullivan.

Twenty-five years prior to the beginning of the opera, Iolanthe, the mistress of fairy revels, who arranged all the fairy dances and songs, committed the capital crime (under fairy law) of marrying a mortal human. The Queen of the fairies commuted Iolanthe's sentence of death to banishment for life on the condition that Iolanthe left her husband and never communicated with him again. After the passage of 25 years, the fairies, still missing Iolanthe deeply, plead with the Queen to pardon Iolanthe and to restore her place in fairyland.

Phyllis cannot decide which of the two selected peers, Tolloller or Mountararat, she ought to marry, and so she leaves the choice up to them. However, Tolloller tells Mountararat that his family's tradition would require the two Earls to duel to the death if the latter were to claim Phyllis. The two decide that their friendship is more important than love, and renounce their claims to her. Meanwhile, the Lord Chancellor has a nightmare due to his unrequited love for Phyllis. The two peers try to cheer him up. At their urging, the Lord Chancellor determines to make another effort to convince himself to award Phyllis to himself.

Although Strephon now leads both parties in Parliament, he is miserable at losing Phyllis. Seeing Phyllis, he finally explains to her that his mother is a fairy, which accounts for a good many things! Phyllis and Strephon ask Iolanthe to go to the Lord Chancellor and plead for him to allow their marriage, for "none can resist your fairy eloquence". Impossible, she replies, for the Lord Chancellor is her husband. The Lord Chancellor believes Iolanthe to have died childless, and she is bound not to "undeceive" him, under penalty of death. However, to save Strephon from losing his love, Iolanthe decides to present his case to the Lord Chancellor in disguise.

Although the Lord Chancellor is visibly moved by her appeal, which evokes the memory of his lost wife, he declares that he himself will marry Phyllis. Dismayed, Iolanthe desperately unveils, despite the warnings of the unseen Fairies, revealing that she is his long-lost wife, and that Strephon is his son. The Lord Chancellor is amazed to see her alive, but Iolanthe has again broken fairy law, and the Fairy Queen is now left with no choice but to punish Iolanthe with death. As she prepares to execute Iolanthe, the Queen learns that the rest of the fairies have all now chosen husbands from among the peers, thus also incurring death sentences - but the Queen blanches at the prospect of slaughtering the whole company of fairies. The Lord Chancellor suggests a solution: change the law by inserting a single word: every fairy who "don't" marry a mortal shall die. The Fairy Queen cheerfully agrees and, to save her life, the dutiful soldier, Private Willis, agrees to marry her. Likewise, seeing no reason to stay in the mortal realm if peers are to be recruited from persons of intelligence, the peers agree to join the fairy ranks. They all sprout wings, and "away go to fairyland".