Ingredients:
Paladin's holy mount
Gargantuan fire beetle
Crippled rogue
Flooded mine
Diary
Intelligent Greatsword
Act I
A Lonely Warhorse
Trekking through the countryside, the PCs notice a resplendent white horse draped with an ornate caparison. Closer inspection -- the horse is friendly enough toward Lawful and Good characters -- reveals the cross and concentric rings of Cuthbert on the caparison, on the saddle, etc. In the saddlebags can be found rations, a few dozen coins, and a written journal.
(Optionally, the warhorse can be fending off a skirmish of Kuo-Toa, up from the depths of the nearby mineshaft. They should be no match for the PCs.)
The diary tersely recounts the past few weeks in the life of Laragon Lawbringer, Paladin of St. Cuthbert. A few key points:
- Battled to bottom of Goblin kingdom of Rathuk Appon to regain the Lawbringer
- Accompanied by Calahan the Clever, who recovered the Sphere of Athoth-Mon, is still determining its powers
- Learned that the Lawbringer's sister artifact, the Helm of Justice, may be in ruins beneath the abandoned mine at [party's current location].
Act II
An Odd Standoff
The PCs can easily find the nearby mine entrance. The upper levels are empty, just an abondoned mine, but deeper they'll find a deep vertical shaft filled with water. On a ledge over that shaft, they'll find a cowering wretch with one leg hacked off and bandaged in strips of his once-elegant cloak. This is Calahan the Clever (Chaotic Good Rogue/Wizard).
What is he cowering from? A Gargantuan Fire Beetle filling the horizontal shaft leading away from his ledge. But the Fire Beetle's stuck. Just out of reach.
Given the chance, Calahan explains that Laragon, in a fit of madness, hacked off his [Calahan's] leg instead of attacking the giant beetle that assaulted them.
(Calahan does not realize Laragon's new-found Greatsword is an intelligent Lawful blade that despises his Chaotic ways. It attacked him.) Calahan, in a panic tossed the Sphere of Athoth-Mon into the gaping maw of the giant beetle -- and it began to grow even more, until it burst through some weak supports keeping a dam in place and eventually found itself stuck.
(The Sphere of Athoth-Mon simply allows its owner to cast Enlarge and Reduce as a 10th-level Wizard.) The bursting water washed Laragon into the vertical shaft, where he surely drowned (in his plate armor). Calahan managed to catch a grip on a wooden support before getting washed over.
Act III
Into the Cold Still Water
If the party can explore underwater, they may dive down the deep shaft until they find the bottom of the digging done by Man -- and they find a (new) opening between the bottom of the mine shaft and a series of natural caverns -- caverns inhabited by Kuo-Toa. There's no sign of Laragon or his Greatsword, Lawbringer.
If the party can't explore underwater, they can magically reduce the beetle -- at which point it can attack -- or they can kill it in place and try to find a way past the chitinous corpse.
Eventually, after working down a few levels toward the water line, they should face Kuo-Toa ambushes -- and they'll still need some way to explore underwater to delve into the Kuo-Toa kingdom and retrieve Laragon's sword.