The appointed time comes, and a portal opens in the wilderness outside Kheldriver.
Hundreds of armoured soldiers file out of it, taking up a position around the magical breach in reality. A small portion of the General's reputed army, but still a significant force.
The adventurers, bravery in their hearts, go to stand before the portal, aware that magic blocks their ability to teleport. Two emissaries stand to the front: one, Shaytessa, a scholar fluent in the language of the Netherese; the other a gnome named Raz.
The negotiations do not go well. By some magical artifice, the General teleports half the skeleton warriors around him to Baldur's Gate, before departing through the portal.
His minions attack, in an effort to slay the adventurers, or delay their return to Baldur's Gate. But with magic and blade, despite heavy losses the adventurers cut their way free, destroying most of the undead and leaving only a handful of the undead legionaries to slink off into the wilderness.
In Baldur's Gate, however, without warning, the undead soldiery appears out of thin air, and many of the murderous skeletons turn their weapons on anything alive - humans, demi-humans and even dogs and cats. Others break into homes and shops, and still more try and hide themselves within the sewers.
At first, the active patrols of the Flaming Fist are surprised and overwhelmed, and blood runs in the streets. But adventurers, after a short delay, teleport back from Kheldriver and lend their aid against the marauding undead, and the tide turns.
A Dawnknight, Eldarian Al'maire takes command in the East Gate. Safe areas are created for citizens while the undead are hunted down. Families are reunited amidst the chaos. The dead and wounded are taken to temples for aid, where possible. Adventurers move house to house, clearing out undead warriors from where they have hidden themselves. And a sweep of the sewers is conducted with the aid of the elven ranger Celduil, cleaning out the upper levels and much of the sewer bowels before the General's soldiers can get too far.
Its said that the Dukes themselves fought in the Palace District, limiting the damage there. In the docks, many citizens ran to the protection of the off duty Flaming Fist in the mercenary company's headquarters, although the tight alleys saw a number of deaths, they also offered many hiding places. The sprawling east gate saw the heaviest fighting, with fires starting in at least one of the city's inns and there being much work for the adventurers to do.
When the fighting dimmed down it became apparent that several hundred citizens had died in the initial attacks, and many more were injured, but the interevention of the adventurers had managed to prevent a much worse outcome. All the undead on the surface appear to have been destroyed. If any are still present in the city, they reside deep in the sewer's bowels.

Duke Eltan gave a speech to boost morale, and Duke Belt thanked the adventurers for their aid. A Silver Rose Knight in the crowd, Lady Elvina, demanded to know how future attacks would be stopped. The fact that the answer to this was delivered privately may mean only one thing.
They don't know.