Act One
Wicked is the prequel to the classic Frank L. Baum novel, The Wizard of Oz. Based on Gregory Maguire's novel Wicked ~ The Life and Times of the Wicked Witch of the West, the musical questions just how the Wicked Witch became 'wicked' - "was she born wicked or did she have wickedness thrust upon her?"

You are first introduced to the green girl, Elphaba, as she arrives at Shiz University, where she reveals a hidden talent for magic. It is here at Shiz that she meets Galinda (who eventually becomes Glinda the Good) when they are paired as roommates. To begin with, they both totally loathe each other and are not happy with the situation they find themselves in.

Galinda hits on an extraordinary plan to show up her roommate when her friends discover a very embarrassing hat that her 'Granny' has sent her. She gives Elphaba the hat, pretending that her niceness is the reason for the gift, when in reality she only wants to make a laughing stock of her green roomie. However, just before Elphaba is about to make her entrance, Madame Morrible appears at the party to give Galinda everything she has ever wanted - a training wand and access to Elphaba's sorcery tutorial. She suddenly has a change of heart, but it is too late to stop Elphaba making a fool of herself.

Elphaba, being the strong person that she is, takes matters into her own hands and tries to shrug off the snipping comments of her classmates and starts dancing away. It is at this point Galinda cuts in, much to the horror and disgust of her friends. Shunning their advice to stop, she carries on and an unforgettable bond starts to bloom between the roommates, and it is only a matter of minutes before the rest of the Oz Dust Ballroom are following Galinda's lead and joining in the dance.

Now friends, life at school is not quite as bad for Elphaba, although the harmony does not last long. Dr Dillamond, the professor she looks up to, is taken away from Shiz, an Animal no longer permitted to teach. This outrages Elphaba and she wants to do something about it, but is prevented by Madame Morrible. Class continues with a new teacher who brings with him a cage sporting a defenceless Lion Cub, and that because of his situation, he is a Lion that will never learn to speak.

No longer able to control her rage, Elphaba's powers are unleashed again. The class and teachers are affected by her powers, but Fiyero is not, giving her and Fiyero the perfect opportunity to rescue the Lion Cub and take him to safety. Alone with Fiyero, Elphaba discovers that there is a possibility that their relationship is something more than just friends. But before she has a chance to pursue it, awkwardness sets in and Fiyero flees the scene with the Lion Cub.

Shortly after, Morrible goes in search of Elphaba with the news she has been waiting for - that the Wizard has requested her presence in the Emerald City. Persuading Galinda (now Glinda) to go with her, the two set off for the wonders of the Emerald City and soon find themselves standing before the Wonderful Wizard of Oz.

In order for Elphaba's 'heart's desires' to be fulfilled, she has to prove herself to the Wizard, and his new Press Secretary, who just happens to be Madame Morrible. The Wizard's monkey servant, Chistery, has always dreamed of flying with the birds, and it is up to Elphaba and a levitation spell from the Grimmerie to make it possible - and she does.

However, she also learns something else that will change her life forever - that the Wonderful Wizard of Oz is not so wonderful after all, and her whole presence and spell-casting a mere set-up to carry out the magic the Wizard could not do himself. And when she discovers the Wizard is responsible for stopping the 'subversive Animal activity,' she refuses to go along with his plan and runs away.

Glinda follows, but they soon find themselves trapped in the attic with the Wizard's guards coming up after them. Morrible announces to Oz that Elphaba is 'wicked', 'responsible for the mutilation' of the monkeys and should be captured. Elphaba now knows she has no choice but to flee. With very few options left, Elphaba attempts the levitation spell, although she fails to develop wings like Chistery. However, the broom starts levitating through the air towards her. Taking it, she has the perfect opportunity to escape.

She pleads with Glinda to come with her, but she cannot. As the guards burst through the door and grab Glinda, Elphaba starts yelling that it's her they are after, not Glinda, and at that moment, she rises into the air, soaring above the guards and away from harm.

Act Two
After Elphaba's escape, the rest of Oz are distracted by the surprise announcement of Fiyero and Glinda's engagement and are suddenly too busy celebrating to worry about the 'wicked witch', although neither Fiyero nor Glinda can get her out of their minds. Surprised by the news of his own engagement Fiyero continues to wave and smile, playing along with the charade until the Citizens of Oz start making 'wicked' comments about Elphaba. At this point, he takes his leave, agreeing to marry Glinda, but no longer able to stay and listen to bad things being said about Elphaba.

Elphaba meanwhile, pays her sister a visit, where she discovers that her father has died and that Nessa is now the Governor of Munchkinland. She begs for her sister's help but is refused it as Nessa reveals she is fed up with Elphaba helping everyone else with her 'powers', but never her own sister.

Casting a spell on her sister's shoes, she is suddenly able to walk and Elphaba has finally had the chance to do something good. Only when Nessa calls for Boq, more secrets are revealed, about what Nessa has been doing to the Munchkins, but more importantly for Elphaba, that Fiyero and Glinda are getting married. Boq, now seeing that Nessa can walk and take care of herself, announces that he is leaving to go after Glinda, something Nessa cannot stand.

Nessa attempts to cast her own spell from the Grimmerie to stop Boq leaving, but it backfires and instead starts to shrink Boq's heart, leaving his life hanging in the balance. The only thing Elphaba can do to help is cast another spell in the hope that his lack of heart will no longer be an issue. She leaves her sister to go to the Emerald City, and when Boq wakes up, he discovers he is now made of tin, and the only thing Nessa can do is blame it all on her sister.

Elphaba arrives at the engagement party, but is unable to get to Fiyero or Glinda without being spotted. She soon discovers she is not alone when the Wizard reveals his presence. She is angry with him, but after some explaining, she can begin to understand what he did. She agrees to join forces with him, but 'on one condition' - that the monkeys are given their freedom. The Wizard agrees and for a few short moments, all is well, until Elphaba reveals Dr Dillamond under a blanket. When she realises he has lost the power to speak, she is furious with the Wizard and vows to 'fight him until the day she dies'.

The guards are called and Fiyero arrives with them. After sending away his men to fetch water, he grabs the Wizard and holds him at gunpoint, while telling Elphaba to leave. Glinda picks that moment to find out what the commotion is about, discovers Elphaba, and then that Fiyero is threatening the Wizard. When questioned what he is doing, Fiyero reveals he is leaving with Elphaba, much to the surprise of both women. The two flee the scene, leaving behind a distraught Glinda who reveals, inadvertently, to Morrible and the Wizard the best way to capture Elphaba.

Together again for the first time since the Lion Cub incident, Fiyero and Elphaba are finally able to be with each other. But again, their bliss is short-lived when Elphaba has a vision of a 'house, flying through the air'. Believing her sister is in trouble, she leaves Fiyero in the forest and goes to Nessa.

On arrival, Elphaba finds her sister dead, killed by a falling house, and Glinda mourning her death. The pair exchange heated words and eventually a fight breaks out, which is only stopped when the Ozian Guards arrive, apologising for their delay. Elphaba is shocked that Glinda used her sister's death as a trap to capture her.

At that moment, Fiyero arrives, despite having been told by Elphaba to stay away. He holds Glinda at gunpoint, forcing the guards to release Elphaba, who is then able to escape. Once she is safely away, Fiyero turns himself in and it is now Glinda realises that he really does love Elphaba, and not her. Fiyero is then stuck on a pole in the cornfield in the hope the torture will make him reveal the wicked witch's whereabouts.

In the safety of the Kiamo Ko castle, Elphaba tries to cast a spell to protect Fiyero and save his life, but when she cannot do so, gives up and she resigns herself to the fact that everyone was right when they called her 'wicked'. She cannot do anything right, and more importantly she cannot even protect the one she loves, and declares herself as 'wicked through and through'.

The Citizens of Oz are rallied together by Boq to go after the 'wicked witch'. Morrible and Glinda turn out to wave them off, and it is at this point Glinda questions Morrible about Nessa's death and learns the truth behind the cyclone - that it was no 'accident'. Having waved goodbye to the 'witch hunters', Glinda knows that despite everything that has happened, she has to find Elphaba and warn her that they are coming for her.

While together, they learn of Fiyero's 'death', and it is the turning point for Elphaba. She surrenders to her fate, but not before making Glinda promise not to clear her name. Having hidden Glinda, Elphaba goes off to face the angry mob and melts away after a bucket of water is thrown on her.

Chistery gives Glinda the little green bottle Elphaba always kept with her. Returning to the Emerald City, Glinda shows the bottle to the Wizard, revealing that Elphaba was his daughter, and that her powers stemmed from her being a 'child of both worlds'. Glinda informs the Wizard he will be leaving Oz, and that she will take over; he willingly agrees. Glinda calls for the guards, and Morrible is arrested and taken away. Glinda is then, still upset from her best friend's death, left to make an announcement to Oz that she would like to be 'Glinda the Good'.

Meanwhile, a Scarecrow arrives at the castle and once the coast is clear, knocks on the trapdoor. Elphaba appears unharmed and thankful to see Fiyero, even if he is not like he used to be. The spell, which turned him into a Scarecrow, ultimately saved his life. While Elphaba wishes she could let Glinda know they were alive, they both know no one can ever know, otherwise they will never be safe. They leave Oz for the final time, knowing they will never be able to return to their home and friends.