The Isle of the Sun and the Isle of the Moons is a sea-based campaign setting from the Dungeon Crawl Classics adventure Moon-Slaves of the Cannibal Kingdom. The setting can fairly easily be adapted to the D20 fantasy RPG, Tales of Argosa which combines fantasy with sword and sorcery, leavened with a touch of horror. The rules also cover naval combat and the RPG lends itself well to an ocean-based jungle setting.

Last month included an introduction to the locations and NPCs of the Isle of the Moons and the Isle of the Sun. This month delves deeply into several adventures that can be found on the minor isles and the area between the two main isles called the Maze of Sunken Ruins.
These adventures all use Dungeon Crawl Classics RPG. Each one has to be converted to Tales of Argosa. The rulesets are similar enough that this conversion should not be too much of a challenge.
For a sandbox approach with some structure, each PC can be given the information listed For the Players. The group of PCs as a whole can then decide which adventures to pursue and in what order.
The information For the GM contains the actual details of the adventure and any secrets or misdirection involved. The GM will have to convert as needed and keep some weird-sided dice handy to run some of the encounters and monsters.
The Black Circle and the Sunken Fens
For the Players
Traverse the maze, defeat the gardens, and find the Black Circle. Once you learn the secret of its teleportation magic, you can activate it and make your way to the Sunken Fens. There, a terrible hound guards a black orb, boon to sorcerers and bane to priests.
For the GM
The Black Circle is described in the adventure, The Dread God Al-Khazadar, in area 1. Instead of leading on to the rest of that adventure, the Black Circle teleports to the Sunken Fens.
Doom of the Savage Kings depicts the Sunken Fens in Area D. The black orb powers up arcane spell casters. However, it curses divine casters. Which PC caster takes the black orb will matter.
The Sea Queen Escapes
For the Players
The Sea Queen has trapped a beautiful princess beneath the sea. The PCs learn of her plight through prophetic and disturbing dreams of watery ruins and dark magic. The Sea Queen plans to sacrifice the princess and flood the surface world to feast on the corpses of those she drowns. Doom is coming soon on the waves.
For the GM
Lies! The Sea Queen and the princess are one and the same. The Sea Queen is imprisoned and wants to break free. If the PCs rescue the princess, they unknowingly release the Sea Queen. Only they will have a chance to stop her.
Tower of the Black Pearl
For the Players
Once every decade, the tides recede far enough to reveal the highest eaves of an eldritch fastness of the most wicked wizard ever to plague the world. Now the mysterious undersea tower is known as the final resting place of the fabled Black Pearl – an artifact of great magical power that those who dare to seek it and wield its eldritch power.
For the GM
Soon, the three moons will align and soon and the tides will recede. The PCs will have eight short hours to explore the tower before the dark waters return. The fabled Black Pearl will be theirs for the taking if they can survive the Pearl’s curse.
The Croaking Fane
For the Players
An ancient temple to the Croaking God has been abandoned. Great treasures can be found there, if the ancient amphibians drawn to the site can be defeated and any traps or curses overcome.
For the GM
The power of the Croaking God is on the wane. The PCs have a chance to rob a temple and gain riches and magic. However, if the frog cult begins to grow in power again, they will not forget this grave insult to their god.
Blood for the Serpent King
For the Players
You have raided an ancient serpent-man vault before and hauled away great treasure. Now you have the clues to find another lost crypt and plunder it for your gain.
For the GM
This crypt is not full of only the dead. An ancient evil cobra monster has many magical treasures. However, it is fully ready and willing to wield those items against any foes trying to plunder its crypt. This monster is unique with its magic item-wielding power. Should be an interesting challenge and a change of pace for the PCs.
Next Steps
An entire campaign can revolve around the Isle of the Sun and the Isles of the Moon. Last month covered the agendas of the three sisters and the resident giant ape. As the PCs work their way through these adventures, they will bump into the machinations of these sisters and the ape. An entire campaign of treasure plundering can be interwoven with the plots and schemes of these four major NPCs. They might even ally with one of these NPCs, but there will likely make direct enemies of the others. The frog cult might return in their slimy ships and perhaps the snake-men will return from beneath the earth or from another adventure to plague the PCs.
In addition to the site-based adventures and the NPCs, other explorers or perhaps pirates may come to the islands in ships of their own. Following the pirates could be navies of other kingdoms. This may lead to further naval conflict or perhaps an alliance if competing navies arrive and the PCs decide to bargain. The explorers may plunder what the PCs want. The pirates might want to found a port of scalawags. The PCs may work with them to set this haven up, or perhaps hunt them and turn them in for a reward from the kingdoms they have plundered. How the PCs interact with the explorers and the pirates will impact how the navies of kingdoms interact with them. Entangling alliances, schemes, and competing power await the PCs willing to explore the isles. Plenty of options to fill an entire campaign.
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