The Black Ring: by Dan Hauffe
This fantasy adventure was printed in Pegasus issue 1
This is actually a series of mini adventures, that could be a small campaign; certainly not a short adventure and I cannot picture how this could be completed in one session.

An adventure for character levels 10-15, but could accommodate higher level characters with a small bit of tweaking by the Judge.
It is set in Hex 3427 of Map 12 of the Judges Guild World (Isles of the Blessed - Magic Realm - though the map is not necessary for play).

The module offers six pre-generated Player Characters that can be used.
Averaging 12th level; Two are LG and the rest are Neutral in alignment.
Although any character alignments could be used; the Judge should know that alignment plays a key roll near the end of the adventure series.

The overall scenario involves the restoration of the Sentinel of Time to its proper balance. In order to reach the Sentinel, the three parts of the Black Ring, an ancient artifact which was torn into three pieces during a battle in the ancient past, must be found and reforged. Most of the overall scenario deals with recovering the three parts of the Black Ring which are scattered on nearby islands. Additionally; the scenario involves a mixture of Wilderness and Dungeon adventure on both sea (not required) and land. Most of the Wilderness adventure is in traveling between the islands and exploring them. Travel between the islands is very hazardous, and unless the players take some extraordinary precautions, they will probably be shipwrecked at least once.

Individually; the Dungeon adventures are short, but dangerous (at least in relation to the supplied characters).
This is not meant to be a pushover. If it appears the party will blow away the monsters, the Judge should feel free to double or triple the number of monsters, or substitute more powerful creatures. On the other hand, if it looks like the monsters will roll over the party, the monsters should be reduced in number and/or power.

A Note which can be given to the players at some point. Perhaps from some drunken sailor who heard the legend and has sailed around the Sentinel Key's:
Kharrapdir was a man filled with pride. To all who came to the Sentinel Keyes he would boast of his power and of his ring - The Black Ring, and above all of his power to reach the Sentinel. And then came the time when he was seen no more. The curious journeyed to the Isle of the Sentinel to see what had befallen the Prideful one. Of Kharrapdir there was no trace, but the ring was there, shattered into three parts. And so was Kharrapdir last of the Keepers of the Sentinel. The parts of the Ring fell into various hands, but always found their way back to each of the other three islands.

PLAYERS INFORMATION - To be given out as the Judge Desires:
Ships coming from the Isles of the Blest have been reporting oddities of weather which could not be explained - sudden hurricanes followed by calm, beautiful sunny days followed by blizzards, etc. The learned and the Wise were consulted, and they determined that these affects were centered on the Sentinel Keyes. Much concern was expressed over this fact since the Sentinel of Time located there was supposed to keep the balance of the Seasons. Therefore in their infinite wisdom it was decided that someone should go to the Keyes and check on the Sentinel.
According to legends, only the possessor of the Black Ring, an ancient artifact of unknown powers, could reach the Sentinel. The Black Ring has been possessed by the Keepers of the Sentinel, Wizards of unknown power who served the Sentinel. It was shattered centuries ago during a battle of the Last Keeper. Since then the pieces have been found at various times, but no one has been able to get all three together, or to remove any piece of the ring from the Keyes.
The highest authorities have determined that it is imperative that an expedition be launched to find the three parts of the Ring and to reforge them.  The reforging will require the following: Three parts of the ring to be present in the same place; a Wish to reforge the ring; and a Rod of Cancellation to recharge the ring.
Judges Note: Although none of those items is available.... it is supposed by the Wise that the Ring has insured that the objects necessary for its reforging are available.

JUDGES INFORMATION:
The Sentinel of Time is a device whose function is the maintenance of the balance of the Seasons, Tides and Heavens. If some magical force upsets this balance, the Sentinel activates to restore the natural order. The Sentinel protects itself with very powerful magical means, and has remained undisturbed for the eons for which it has existed. Only the Keepers of the Sentinel, possessing the Black Ring, were able to approach it. But the Keepers are no more and the Black Ring has been broken. Recently a wizard of some power has attempted to gain access to the Sentinel, wishing to control it. His attempt ultimately failed, but the artifact which he used in his attempt was able to penetrate the Sentinels defenses, and now lies on top of the Sentinel.

This artifact, Ardissan's Skull, is sentient with malevolent intentions of its own. By its power and presence, it has disturbed the flow of information to the Sentinel, altering the true incoming information so that the Sentinel believes that the balance is off: causing the Sentinel to believe it needs to restore balance; so it has started realigning the local weather and other events, which is making things more chaotic by the day. So far these events and weather changes are mostly local to the isles, but the effects are expanding and will eventually spread through the known realms.

There are four islands total which are to be visited by the adventurers:
The first three islands are where the group will gather the three parts of the Black Ring and the other "Key Items" they will need to reforge the Black Ring and recharge its powers. Without all three parts of the Black Ring and all of the "Key Items" listed below which are all required to reforge the ring, the adventure group and in fact the entirety of the known Realms are doomed.

Generally speaking: Each island has deadly traps and/or creatures.
In addition to the "Key Items" listed below other magical and non-magical items are available through encounters and as hidden objects to be found for the PCs to use.

Carrasthinian's Isle - A lich (Carrasthinian) has one portion of the ring along with one item that can help restore the ring, plus a small forge which is also needed.
Even though the book lists him at only 12 HD, the Liche is both powerful and very cunning and he has a battle plan mapped out which is complex and very deadly to any group of PCs. This isn't your normal undead dude and for this scenario Carrasthinian acts as a 20th level MU and knows spells from 9th level and below.
The proposed battle plan (as written) is a thing of beauty which should not be ignored by the Judge.

Key Items:  
1) Tapestry - which if studied will show the PCs how to best gain access to the tunnels of the Sentinel.
2) Small Forge and other items needed to reforge the ring
3) a ring fragment

Isle of Hestrin - Golems, animated statues and the tomb of Hestrin.
This one is filled with traps and animated statues that are quite deadly, along with Golems of Flesh/Stone/Iron.

Key items:
1) Rod of cancelation - inside the tomb of Hestrin
2) a ring fragment (it is not listed, but by process of elimination it must be here. the Judge should place it where he/she feels is best)

Isle of Lonesome Shoulders -  Several Ogre Magi and their master (A human mage) and the Statue of Anubis which is dangerous in itself (Undetectable Magical Trap)

Key items:
1) Rod with Limited Wishes (one wish remains) - inside the Statue of Anubis (left thumb)
2) a ring fragment

Isle of the Sentinel - Main encounter - this portion of the module is a thinkers crawl.
The characters will not be able to access key areas or even survive this islands interior without the re-forged and recharged Black Ring and even with it they risk certain death if they make mistakes.

Key Items:
1) Ardissan's Skull - Hall of the Sentinel (6)
2) Sentinel of Time