Deep within a temperate wilderness, a sheer cliff hides a den of predators who strike from the shadows and disappear into the canopy. Cave of the Spiders is a high-stakes D&D 3.5 adventure designed for 9th-level characters. Originally penned by Skip Williams—one of the primary architects of the 3rd edition Monster Manual—this module is a masterclass in utilizing verticality, environmental hazards, and the deceptive power of the Aranea. It serves as an intense hostage-rescue mission or a grueling site-based crawl through a vertical labyrinth of silk and stone.
Introduction: The Ambush at the Cliffside
The adventure centers on a group of “unusual bandits” led by the crafty and greedy Mettik. These are not simple highwaymen; they are a sophisticated cabal of Araneas—shapeshifting spider-sorcerers—who have leveraged their ability to mimic humanoids to infiltrate and plunder woodland communities. With bugbear muscle and monstrous spider pets, they have established a formidable stronghold that tests a party’s tactical positioning as much as their combat prowess.
Narrative Core: The Spider’s Larder
The emotional hook of the adventure lies in Area 6 (The Prison). Here, Mettik keeps his “stock”—a collection of humanoids bound in silken cocoons like flies. Among the victims is Genevieve de Guare, a merchant who offers a staggering 5,000 gp reward for her rescue. This high-value reward creates an immediate incentive for the players to push through the lethal vertical shafts of the complex, even as the Araneas use their sorcery to peel the party apart.
Tactical Breakdown: A Vertical Gauntlet
The “Lair” is uniquely mapped as a side view rather than a traditional top-down floor plan, highlighting the verticality of the encounters.
1. The Gatekeepers (Area 1)
The entrance is guarded by three Bugbear Warriors and an Aranea Sergeant.
- The Tactics: The bugbears use masterwork composite longbows to rain fire down the scree slope, while the Aranea uses Ray of Enfeeblement and Web to pin intruders in place for the bugbears to pick off.
2. The Main Shaft (Area 4)
This is the tactical highlight of the module. A steep, slippery slope leads to an “abyss.”
- The Drawbridge Trap: The Aranea sergeant on the upper platform can lower a bridge to welcome “guests,” only to drop the mechanism and send intruders plummeting 50 feet into the darkness of Area 5.
- Vertical Combat: Players must manage Climb checks (DC 20) while being pelted by javelins and spells from above.
3. The Barracks (Area 5a)
While the Araneas are the brains, the sixteen Bugbear Guards are the brawn. Half of them are usually sleeping, but the sounds of combat in the shaft will bring them rushing out. A 9th-level party that isn’t careful can easily find themselves swarmed by heavy-hitting melee combatants in the cramped quarters of the landing.
The Boss: Mettik (EL 9)
Mettik is an Aranea Sorcerer 5, making him a CR 9 threat. He resides in a surprisingly opulent bedchamber (Area 9) filled with silk cushions and jade lamps.
- The Tactics: Mettik is a master of defensive sorcery. He pre-buffers with Displacement, Shield, and Resist Energy. In combat, he uses Shout to disorient the party and Suggestion to convince the group’s frontliners to simply leave the cave.
- Hybrid Nature: He alternates between his elven form for social deception and his spider-humanoid hybrid form to utilize his Poison (DC 16, Strength damage) and Web abilities.
Mechanics & Hazards: Scree and Silk
Skip Williams utilizes environmental mechanics to great effect:
- Scree Slopes: The loose rock outside the cave makes movement difficult and provides a penalty to Stealth, ensuring the guards always have a “heads up.”
- Ettercap Sheet Webs: Hidden traps (Search DC 15) that entangle players, leaving them vulnerable to the Huge Monstrous Hunting Spiders‘ tremorsense ambushes.
System Conversion: 3.5 to 5e and OSR
This module relies on classic monsters, making it an easy port.
For 5th Edition (5e):
- Mettik: Use the Aranea stat block but grant him additional spells equivalent to an 8th-level Sorcerer (Sunbeam or Blight for a darker feel).
- Verticality: Use the Falling rules (1d6 per 10 feet) and ensure the Aranea uses its Climb speed to stay out of melee range.
For OSR (Old School Essentials/Shadowdark):
- The Strength drain from the spider poison is particularly lethal in OSR. Provide the players with a chance to find an antidote in the Aranea’s lab or from a rescued prisoner.
GM Tips: The Fog of War
- Use the Acoustics: Combat in the vertical shaft (Area 4) echoes throughout the lower levels. Have the guards in Area 8 lower their knotted rope to reinforce Mettik immediately.
- The Ransom Hook: If the players rescue Genevieve, don’t make the payout easy. Have a rival merchant try to block the payment or claim she is an Aranea imposter using Disguise Self.
- Visual Descriptions: Emphasize the “Mother-of-Pearl” history of the tower (if linked to Bad Light) or the oppressive, sticky nature of the silk-covered walls.
Conclusion: A Masterful Use of Space
Cave of the Spiders is a compact but punishing adventure. It rewards players who think in three dimensions and punishes those who charge blindly into its silken traps. For a 9th-level party, it provides a high-stakes rescue mission with a memorable villain and a truly generous hoard of loot.
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