Traveling along the Deep Forest Road, the PCs meet a landed knight who's manor is being threatened by giant spiders!
The PCs could be delivering a package to one of the towns or even to Sir Aerik (the knight involved) himself, or they could be on their way to another, completely unrelated adventure.
Sir Aerik holds a manor and some land in the area North of the Deep Forest Road. Two tenant farms on his lands have been attacked by giant spiders, a rarity in this part of the forest. The giant spiders have destroyed the farms, covered them in webbing and drained the animals dry but no trace has been found of the farmers or their families. The knight is very concerned and so are his tenants.
While the knight is talking to the PCs, another farm is found attacked. If the PCs investigate, they find that a group of farmers and the knight's retinue already there, ruining any chance to find tracks. The farmers are armed with pitchforks and make-shift spears and they are rife with rumors and friend-of-a-friend sightings of giant spiders in the woods.
The farm is all-but destroyed and the family is missing. The few farm animals are strung up with webbing and drained of their blood but barely cocooned in webbing. Any PC who has fought giant spiders or been in giant spider nests will be suspicious and know that spiders don't do this - they cocoon their prey, inject in poison and then drain the body into a dry husk.
A careful review of the farm (and of the other destroyed farms) shows that small items of value are missing but it's hard to see that among the wreckage. Questioning the missing families' closest neighbors will provide clues to what valuable items are taken. This doesn't match the M.O. of giant spiders, but of bandits!
The bandits, lead by Zimvan the Elf, have quite the scheme going. Attacking the farms and pretending to be spiders was easy. The bandits outnumbered the farmers and Zimvan used his Sleep spell to good effect. They trashed the farm, took things of value and Zimvan used his Web spell to create the illusion of giant spiders. They drained the farm animals of blood and made their escape, bound captives in tow, with no one the wiser.
These attacks were not just random as Sir Aerik and Zimvan have a long, hateful history. Any chance that Zimvan takes to damage Sir Aerik and his lands are well worth the value to the elf.
PCs examining the area just outside the farm yard will turn up a fairly new trail, going off into the woods. This trail leads directly to a web-filled cave. Tracks found along the way reveal a group of humans went this way some time before.
A few bandits guard the cave opening, hidden in webbed hunting blinds, while, in the bowels of the cave, the rest of the bandits are busy selling the captives from the three farms to some Morlocks!
Zimvan; Elf, Level 3; Alignment: Chaotic; Armor Class: 4; Hit Dice: 3d8, Hit Points: 12; Attacks: longsword (1d8); Save: E3; morale: 8, Special abilities: elf abilities, Spells (Sleep*, Charm Person*, Ventriloquism, Web*, * denotes prepared spell).
Bandits; No. Encountered: 1d6+3; Alignment: Chaotic; Armor Class: 7; Hit Dice: 1d8; Hit Points: 6, 5, 5, 4, 4, 3, 2, 2, 1; Attacks: axe or short sword or spear (1d6), dagger (1d4), short bow (1d6); Save: NM1; morale: 6.
Morlocks; No. Encountered: 1d4+3; Alignment: Chaotic; Armor Class: 8; Hit Dice: 1d8, Hit Points: 8, 6, 5, 4, 3, 1, 1; Attacks: short sword (1d6); Save: F1; morale: 9; Special abilities: 90' infravision.