From the description, and the title, it's not exactly clear what this evening's entertainment is going to be about. The premise is that across London, on a morning in Autumn 2011, twelve people wake up after having had the same frightening dream. So it's about coincidences then. Another character, the thirteenth one would suppose, let's call him John, as that's what Bartlett's called him, has just gotten back into town after being away for years, and he's not that impressed by the economic gloom, ineffective Government and apathy amongst the populace that he finds. He actually has a strong vision for the future, and a way, he thinks, of making it happen.
So it's not just a play about coincidence, it's also a play about the power of the individual, and the importance of believing in things. Which, though these themes sound quite general, sounds like something we could do with watching in the here and now.
If you want to find out a bit more about Bartlett, a bit of a theatrical wunderkind, this is a good profile in Prospect Magazine, where he also speaks about 13. Among other things.