As directed by Lord Nasher. my party have explored Mirabar and it's mines, Port Llast, Luskan, the ground level and dungeon of the Hosttower, and we've got the Diamond Orb and the Ruby Orb.
But I can't enter the second level of the Hosttower and going through all my screenshots I see there are supposed to be five Orbs, but I have no idea where the other three are.
After getting the second Orb I returned to Lord Nasher, but he was busy, so no help from him.
Looking in the editor the dungeons are not listed in "chronological" order, and I can't see that I've missed anything in the Hosttower.
The stairway to the second level of the Hosttower is blocked by a "vortex" that pushed the party out. From what I've gathered from the editor entering the vortex completed a quest stage.
So presumably I need to complete yet another quest stage somewhere else, and then return to the Hosttower for the finale? But where am I supposed to go? Have I missed something, or am I supposed to just explore all towns and ship destinations?