Basically, my fort was divided into three parts by bridges: one trap-lined entrance corridor, one floodable corridor after that, and my main fort. Well, what happened was that a goblin siege just happened to coincide with the arrival of a human caravan. I, in my infinite foolishness, decided to wait until the humies enter the fort, and then drop some siegers into the drowning pit under the first bridge. So, the humans arrived all right, but the first sieger was a War Cave Dragon. The others seemed to fall behind, so I just thought I'd let him in, and then raise the bridge.
I made a fatal mistake.
Specifically, I didn't account for dwarven stupidity.
Let me give you a description of the events. The cave dragon rushes through the bridge, but he is intercepted by a macedwarf halfway through. The macedwarf flies off his rocker and goes medieval on the poor beast, bruising its innards, breaking its legs, wings, and other appendages, but, being a macedwarf, he can't seem to actually kill the wretch, and its bruised carcass prevents the bridge from being raised. Another cave dragon arrives, crosses the bridge (completely ignoring the macedwarf currently whaling on its comrade) and then he sees him. The Mule. His dragon heart overflows with hatred. He bullrushes the creature, grabs it by the head, and starts shaking it around, spraying blood all over the place. The human caravan guards promptly surround him and pull his head through his rectum. The mule goes berserk with pain, kicks the human merchant in the lower body, and runs off into the corridor, where it is bisected by a -large bismuth bronse serrated disc-. The macedwarf continues to abuse the dragon. The merchant retches. And then...
The rest of the siege arrives. They slaughter the macedwarf and the guards, but the merchant somehow escapes them. They chase him through the killing corridor, a cage trap dispatches a Hammer Lord, and the rest of the dragons refuse to follow, for some reason. The abused dragon has crawled off somehow, so I drop the goblin stragglers into the pit. The rest of the goblins pass the trap corridor with significant losses (~65%) and engages my military. This is where I found out that my marksdwarf squad hasn't been issued ammunition, and one of my two melee squads has somehow failed to arrive to their positions. The marksdwarves are promptly slaughtered, excepting their captain, who is a badass. The other goblins are dispatched by my BSDM melee squad, The Conquerors of Whipping, but not their leader, whom I shall call Boris (Baseborn Orifice Ravaging Imbecile Sonovabitch), a goblin swordmaster. My remaining five fetishist dwarves chase him around, while the marksdwarf captain has decided to screw off to the hospital for a nap and a refreshing drink.
By now I am sure of my success, being only a Novice DF Player who hasn't encountered a goblin swordmaster in melee before. Well, Boris lops off my militia commander's hand, kills two other dwarves, receiving the title of Boris the Bastard of Eviscerating, before I even notice that something is wrong. In frustration, I decide to flood the corridor to drown him, but fail to account for the fact of the second bridge being lowered (it blocks the water flow when raised), so I only end up muddying everything and spreading merchant vomit all over the place.
In a completely unrelated (I do so swear) accident the living quarters become flooded, preventing my 68 civilian dwarves from sleeping. Everybody is damn miserable already, since we have lost some dozen soldiers plus a half-dozen idiot civilians who got caught outside. Boris finishes mutilating my hapless soldiers, of whom only the militia commander and another macedwarf escape, and decides to just camp in the trade depot with the remaining dragon, since the bridge is raised. I lower the bridge, and he walks off into the sunset, his extremely long hair billowing in the breeze. The dragon remains stationary, since he can't be bothered. The rest of the military goes and shows him his error, losing another hammerdwarf in the process.
The mayor throws a tantrum and deconstructs the second bridge, while some other bastard deconstructs the first. The remaining macedwarf goes berzerk because her husband was killed in the attack. So now she's caught between the first bridge and the second with only some children to keep her company. The fort is in a tantrum spiral.
A Russian adage goes, "Why love, why suffer? I'll go eat and go to sleep". I think I'll follow the advice. If there is a single living being in the fort by morning, I'll make love to my goggles. Do excuse me for the wall of text, I just had to tell someone the whole story.