Expedition to the Barrier Peaks is a high-level sci-fi/fantasy adventure included in the collection of beloved adventures Quests from the Infinite Staircase. This eccentric adventure that takes players to the crash site of a spaceship was originally written by Gary Gygax, features the first appearance of the froghemoth, and is Stephen Colbert’s favorite D&D adventure of all time!

Read on to learn more about exploring the ship’s many levels, avoiding strange alien hazards, discovering technology like laser pistols and antimatter rifles, and meeting all types of machines, from simple worker robots to supercomputers!

Warning! This article contains minor spoilers for Expedition to the Barrier Peaks. If you want to experience this adventure for the first time as a player, you’ll want to turn back now!

• Expedition to the Barrier Peaks Adventure Overview
• Monster of the Week: Froghemoth Elder
• Expedition to the Barrier Peaks Adventure Hooks
• Does This Antigravity Belt Make My Axe Look Big?

Expedition to the Barrier Peaks Adventure Overview

Artist: Michele Giorgi

Character level: 11 – If the table is using story-based level advancement, players reach level 13 by the adventure’s conclusion.

Location: A recently unearthed spaceship that crashed long ago.

Themes: Discovery and exploration, first contact, machine consciousness, suspense, science fiction

Adventure Premise

Many years ago, an unknown civilization built a spaceship and looked for a new planet among the stars. They brought with them many specimens from their home world, presumably intending to introduce them to their destination planet. The ship then crash-landed into a mountain range known as the Barrier Peaks, lying dormant for hundreds of years until a recent earthquake disinterred part of the wreck.

Now, predators are emerging from the site of the crash, leaving no survivors at nearby settlements and outposts.

Uncover the Mystery

Will your party adventure to the Barrier Peaks? If so, consider whether they are motivated by a desire to protect nearby innocents, discover new technologies, or simply collect a bag of gold from the local feudal lord.

Expedition to the Barrier Peaks is a suspenseful sci-fi dungeon crawl that encourages players to explore the entire ship and solve the mystery behind its crash. This is no easy task. A suspense adventure needs unnerving elements, but too many of them could cause the adventure to veer into outright horror.

In a mystery, the suspense should also pressure the players into solving the question at the heart of the adventure: “What happened here?” The dungeon should also feature encounters with lighter moments to break up the constant rising tension—but too many of these would impact the adventure’s mood.

Expedition to the Barrier Peaks strikes the right balance, deftly using suspense to encourage the characters to solve its underlying mystery while keeping things just a little silly.

Dangers You’ll Encounter

This adventure focuses on combat and exploration, though many encounters can be resolved by roleplay instead of violence.

The ship itself is full of dangers: pools of radioactive liquid, patches of dangerous fungi, escaped specimens from the ship’s home world, and newcomers that have arrived in the time since the crash site was unearthed.

As characters explore the ship, they must find and collect colored key cards to gain access to new areas. Some key cards are necessary to progress the plot, while others help the party access treasure or temporarily gain NPC allies.

You’ll also meet Aphelion 3000, or Alphie, the ship’s supercomputer who has lost some of its functionality and needs help with repair, maintenance, and research tasks around the ship. If you befriend and assist Alphie, it can aid your journey; conversely, if you antagonize Alphie, it can make your journey much more difficult and perilous.

Sci-Fi? In my Swords and Sorcery?

Expedition to the Barrier Peaks was Dungeons & Dragons’ first foray into science fiction. What better way to blend a dungeon-crawling game with science than to use a spaceship as the dungeon?

This adventure gives players a brief tour of the genre, asking fundamental sci-fi questions like "Are my ethical obligations toward a sentient supercomputer different than toward a robot or other machine?" and "What is the most responsible way to protect the local environment from an alien invasive species?"

Expedition to the Barrier Peaks also introduced the vegepygmy and froghemoth.

Monster of the Week: Froghemoth Elder

The bullfrog is a voracious predator, eating basically anything that fits in its mouth. It remorselessly snaps up its prey, crushing it in powerful jaws and gulping it into a corrosive stomach, often while still alive.

Now imagine that, but it’s the size of an elephant, and it has four tentacles and three eyes. You have the froghemoth!

This Monstrosity has been terrorizing adventuring parties since 1980, when Expedition to the Barrier Peaks was first published. The civilization that developed the crashed spaceship brought a froghemoth with them, which has since escaped captivity. Living on a spaceship for many years has warped this specimen’s mind and body, turning it into a new and even more powerful creature: the froghemoth elder.

Froghemoth Elder Features

Having lived in such an unnatural environment for many years, absorbing the strange ambient energies, the froghemoth elder is stronger and more resilient than its counterpart. It’s also just a little bit psychic. Without giving too much away: The elder is the same creature size (Huge), but it boasts more Hit Points, a longer reach with its tongue, and higher DCs to escape its grip. DMs will also find that the elder has two unique Reactions and new lair actions to challenge your high-level party.

Froghemoth Elder Tactics

The froghemoth elder is an opportunity for DMs to strike fear into the hearts of the PCs. Frogs consume with lightning speed and absolutely no remorse, staring out into the world with a blank, unfeeling expression.

When running the froghemoth elder, don’t hold back. Gobble up as many PCs as you can, quickly and ruthlessly. At level 11, characters can probably deal enough damage to the creature to escape—and if they can’t, either because they don’t deal enough damage or because they fall Unconscious, that’s all the more dramatic. Then the PCs will have to find a way to rescue their comrade, either by letting themselves be swallowed by the froghemoth or by killing the monster before their friend fails a third Death Saving Throw.

Expedition to the Barrier Peaks Adventure Hooks

If your players need any reason to explore a crashed interplanetary spaceship other than "Because there are laser guns," the book provides a few options to choose from:

Nafas the Noble Genie

Quests from the Infinite Staircase introduces the noble genie and optional group patron Nafas, which makes it easy to get your adventuring party to the spaceship’s crash site. Nafas resides in the Infinite Staircase, an interstitial dimension that players can use to travel from one realm to another.

As with every adventure in the book, things kick off with Nafas hearing a wish from the far-flung reaches of the universe. Nafas hears a wish crying out from the stars, a message of distress from someone "trapped within a mountain of steel" who Nafas suspects "might be the last of their kind." The generous genie then charges the party with freeing the source of this distress call.

Strange Specimens on the Loose

If you aren’t using Nafas as a cosmic quest-giver, Quests from the Infinite Staircase recommends other options that consider the more practical consequences of a spaceship being suddenly unearthed.

As specimens (both mechanical and biological) escape the ship and spread out into the countryside, any settlement near the crash site would be at risk from the spaceship’s inhabitants. The book suggests a specific nobleman from Greyhawk that calls upon adventurers for aid after outposts and towns are destroyed by unknown creatures, but you can just as easily apply this concept to any setting.

If you are using Expedition to the Barrier Peaks as part of a longer series of adventures for a single party, you may want to consider using a personal connection, such as a beloved NPC that the party previously rescued, to call for help.

Advanced Tech

If you don’t think your party will be motivated by money and they don’t have any allies endangered by the ship’s inhabitants, perhaps they’ll be motivated by discovery! Quests from the Infinite Staircase recommends hooking players with the prospect of new technology and groundbreaking scientific revelations. Players might be hired by an inventor or a collector, or perhaps they hear rumors of new strange devices seen in the mountainside and want to beat other scientists to the discovery.

Try to tailor the adventure hook to what is likely to motivate your players’ characters—and feel free to mix and match! You might tempt the party’s Artificer or Wizard with the opportunity to study new technology, hook the Cleric in by informing them that many of their god’s worshippers live in the settlement near the crash site, and remind the Barbarian that one of those worshippers is their sibling.

Does This Antigravity Belt Make My Axe Look Big?

The spaceship is full of advanced technology from another civilization. That society doesn’t seem to have possessed what we think of as classic magic items like the Wand of Magic Missiles or Staff of Healing, but boy did they have plenty of weapons and armor.

In this adventure, you’ll find antimatter rifles, laser weapons, powered suits of armor, antigravity belts, and new types of grenades and pistols. Keep in mind that most of this technology requires an "energy cell" to function; you’ll find these cells—some with a full battery, others quite low on power—throughout the spaceship.

The ship’s supercomputer, Alphie, will pay you in technology if you complete its tasks and help it clean up the ship. If you’ve already found these items, Alphie can provide you with energy cells to fuel them.

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Releasing July 16, you can preorder a digital or physical copy of Quests from the Infinite Staircase from the D&D Beyond marketplace, or preorder both to save money on your purchase!

See you in the Barrier Peaks!

Damen Cook (@damen_joseph) is a lifelong fantasy reader, writer, and gamer. If he woke up tomorrow in Faerûn, he would bolt through the nearest fey crossing and drink from every stream and eat fruit from every tree in the Feywild until he found that sweet, sweet wild magic.