I'm preparing to run my table through the "Dragon Season" phase of the Waterdeep: Dragon Heist adventure on Spring setting, but there's one thing that looks like its going to be a big problem: the entrance to the vault.
First off, it seems almost impossible to find. All they know is that it's somewhere
below the theater.
But this is a super big map, with something like 15 rooms, only one square of one of which actually contains the door. Additionally, it's a hidden door with a DC 20 Perception check to notice. Not passive Perception, but Perception. They have to be actively looking for it. This from a table that hasn't looked for (or found) a secret door in this campaign yet.
It seems exceedingly unlikely they'd manage to make a check in the right spot, and even if they do, most likely they won't find it because the DC is so crazy high.
But it gets worse. Say I rule that the stone tells them exactly what square to search (pretty sure I'm actually going to have to do this). Well, opening it requires a knock spell (which they don't have), or a DC 30 Strength check. Even the barbarian can't make that without a nat 20.
I suppose I could also rule that the stone knows the password for the arcane lock spell, but that seems a bit much (and it looks like it would only drop the athletics check to a 20?).
How are they supposed to get in? Has anyone else run Spring, and if so, how did your table get past this?