Part Two: Perestroika continues on exactly where Part One: Millennium Approaches leaves off - New York City 1986. At the end of the first play, Prior Walter is visited by the angel in an emotional and theatrically compelling scene. The concept of fantasia is only a flirtation in the first play, but is fully exploited in the second. As the latter play unfolds, Kushner uses the powerful devices of theatre and the fantasia to lay out his theories of God, heaven, and humanity. Without going into the specifics, Kushner presents to us the idea that, yes, there is a God who created the universe and there are angels. But his twist on the idea is that the angels are actually lost. God left us. The Angels are waiting for him to come back but humanity is moving ever faster and forward, creating more and more social problems, political schisms, and global conflict. The angels want us to slow down, stop migrating, and wait for God to return so that harmony can be restored. Wow. 
The conflict presented in the fantasia and in parallel in real life in politics, religion, and society is that we can't do what the angels in the fantasia want. As Prior Walter ultimately does reject the angel's proposal in the fantasia - so does he reject the idea in real life too. He does not accept his boyfriend back, instead he moves forward. He does not initially accept the AZT medicine for his disease, but he does move forward (whether or not he eventually does, one can only speculate), Joe's mother rejects her hateful religious beliefs and moves forward a more enlightened human. Most of all life itself moves forward.
After 7 hours, I was emotionally exhausted and intellectually drained, but not so much that I couldn't walk away hopeful and optimistic. Kushner's play is a brilliant work of our time and the fine actors on stage at the Signature Theatre provide it the voice he intended it to have.
The great work has already begun.