This is the last song from Act I. The witches have been declared outlaws, and the Wizard has sent all the Emerald City Guard to capture them, and they've barricaded themselves atop a tower.
The set was non-stop eye-candy with about 43,000 different gears and sprockets in it, and the change-up to LED-driven art-deco lighting whenever they were in the Emerald City was pretty cool too. Great costumes, and oh, good music too. Thanks to my brother and sister-in-law for the ticket, I had a great time.