A review copy of “Greenhouse of Nightmares [PLL-1]” was provided by the publisher. Find more DMs Guild Reviews on my website and YouTube channel.

Support my work by using affiliate links for shopping and pledging via Patreon.

Designed by: Zeke Gonzalez

How do you design or play a Tier 4 (level 17+) adventure? In five years of playing Dungeons & Dragons fifth edition, our campaigns have all ended around level 12. By level 17 surely the player characters are hopping between planes and punching elder gods in the mouth.

Or maybe they’re dealing with a medusa lich. Greenhouse of Nightmares is a Tier 4 adventure featuring a highly thematic dungeon crawl through a unique botanical research lair, with an epic final boss fight.

Greenhouse of Nightmare is a part of a series called Pretty Little Liches. I haven’t looked at the others but they’re each designed as a high-level dungeon crawl with a unique lich villain at the end, each with their own nefarious plans.

Thymia is a medusa lich who didn’t exactly come out of two monstrous transformations with a cheery disposition. The former wood elf druid has taken up residence in a research lab, concocting mutated experiments to fight back against the toxic incursions from nearby industries and farmland.

It’s a neat idea for a dungeon crawl, though not exactly the world-ending threat that I would expect of a Tier 4 adventure. The dungeon design feels more like a Tier 2 or 3 adventure with a massively up-scaled final confrontation.

dms guild review

That being said, the actual dungeon design is fantastic, with multiple entrances, traps, social encounters, and battles with new or re-skinned enemies to fit the theme of a mutant greenhouse. I also appreciate the detailed random encounters in the surrounding wetlands, including quicksand, petrified research assistants, and an ambush by a creepy centipede-monster called a nightshiver.

Other new monsters include a CR 6 Deathshaker (giant cicada), an upscaled flail snail called a Lou Carcohl, and the massive CR 19 Blister Beetle that serves as Thymia’s incredibly powerful pet. The adventure also does a great job taking existing enemies and re-skinning them to fit the mutant nature theme such as with a giant carnivorous plant (roper), giant mosquitoes (stirges) and some giant beetles (triceratops).

Throughout the first half of the complex the party can find Thymia’s Yuan-ti research assistants, bargaining with them, threatening them, or killing them, as well as her night hag mentor, who’s grown weary of the whole facility. Mutated animals can be restored back to their humanoid forms and allied with, and even the final boss herself can be negotiated with using a Skill Challenge.

Hopefully the players are itching for a fight, however, as Thymia’s CR 26 statblock is impressive. She’s a 9th level lich spellcaster, plus the medusa’s petrifying gaze, plus a bunch of crazy Legendary Actions, including shapechanging into an Ancient Green Dragon!

Alas the one area the dungeon falls well short is the map. As a VTT user I don’t like the Dyson Logos art style, and we don’t even get a separate player map (and it’s 10-ft scale, which is a no-go). With a better map, Greenhouse of Nightmares would easily be one of my favorite high-level dungeon designs, even if the overall plot and threat is a bit beneath Tier 4 world-saving heroes.


  • Fun dungeon theme.
  • Detailed random wetlands encounters.
  • Excellent balance of combat, social, and exploration.
  • Final battle includes optional negotiation and an epic multi-stage boss fight with a spell-casting medusa lich.
  • Multiple conclusions depending on player choices and adventure hooks.


  • Dyson Logos map-style; no separate player map handout.
  • Most of the adventure hooks doesn’t warrant a Tier 4 party.

The Verdict: Greenhouse of Nightmares features a highly thematic, well-designed dungeon crawl with new high-level monsters and an epic final boss fight.

A review copy of “Greenhouse of Nightmares [PLL-1]” was provided by the publisher. Find more DMs Guild Reviews on my website and YouTube channel.

Support my work by using affiliate links for shopping and pledging via Patreon.