The custom scenario consists of the Act, Agenda and Location cards. The Encounter deck is entirely drawn from the core box.
In terms of playing the scenario, it felt a little directionless. Also, it was way too hard. I don't want to give away any spoilers, so I'll just say that at the cost of free, you should definitely check it out. I will say that I'm motivated to give custom scenario creation a shot and see how it works out. I have a couple of ideas to work on.
