Sigh.. Got killed by a bogeyman inside a civic mound with four other dwarfs sleeping soundly. I'm not sure how it happened.
Basically, I wandered down to a group of hillocks. The first one was deserted, but I found a goblin commander in the deserted civic mound. He was unarmed, so my travelling companion dispatched him quickly. We moved on to the next hillock which was apparently occupied. Aha! I thought. It must be the goblins. So I offered to help with an insurrection. The drunk I was talking to quickly agreed (as drunks do) and we set off. We didn't get 10 steps, though, when he wandered off. I looked at our agreement and apparently it was satisfied. The occupation was overthrown....
We wandered to the next hillock and noticed an encampment of sleeping humans.... Odd... there were no rumours of armies... At this point I decided to head off to the neighbouring goblin pit. But there was no pit... just trenches... also odd. So we made our way back to yet another hillock when I discovered that my companion was missing. I made an attempt to find him, but he had just vanished.
I made it back to the hillock before dark and started telling stories of all the neighbouring hillocks to try to piece together what was going on. It seems that the hillocks were all conquered by the goblins in about year 30 (it was now 252). At the same time they started on the pit that I had explored (er... found to be missing). It seems that just prior to construction they were wiped out by a titan. At least one mystery solved. The goblins continued living in the dwarven hillocks until one month before I arrived. At that point the humans wiped them out (which was probably the sleeping army I discovered). I'm not sure why their occupation failed, but I suppose it's possible that I scuppered it (by doing nothing...)
Anyway, I asked to stay the night, thinking I would go back to look for my companion the next morning. But half way through the night I was awakened by cackling. WTF!? A single (?) bogeyman was inside the civic mound with me and the 4 other residents. The 4 residents continued sleeping (thanks guys!) and I was no match for the bogey man. Thus ended my adventure.
I'm not sure if it's a bug, or if some weird political upheaval caused the civic mound to be deserted at the exact time I was there. Anyway, this is part experiment to run a fortress and go out and explore every year in adventure mode. So I will definitely be sending someone back there next year to see what's going on.