I listened to this "podcast" out of order because I didn't realise that there was a first series and thought they were stand alone stories so I started with Series 2, then 3, realised I should go back to 1 to get the background and am about to start Series 4. I've been listening non-stop on every car journey I do. It is utterly brilliant.
If you like other worldly phenomena like UFOs, witches and evil reincarnations then this is the Series for you. There are a lot of characters spread throughout the first 3 series (and I assume No.4 once I get to it) so sometimes it's a bit hard to keep track of who is who. Some of the history in the drama involves real people like John Dee, Aleister Crowley - so are the stories based on fact or is it all pure imagination? It makes you want to do some internet sleuthing yourself. And the cliff hangers! You've just GOT to listen to the next episode immediately.
Someone has got to make this into a TV series.