Rooster perpetually interrupts the perpetual card game in the warren, summoning Huck, Fin, Blameless, and Silly to his office.
This time it seems the Watchful Order of Magists and Protectors took their watchful eyes off a shipment of unicorn horns on the recently-missing Golden Merchant cargo ship. The Order paid in advance, declining shipping insurance, so it’s up to R&S to recover the valuable horns. Any valuable extras that can be pilfered from the salvage shall be regarded as icing of profit on the cake of payment. Epi Glottis has all the details.
Down at the docks, the adventurers find Epi Glottis working on his brass barrel masterpiece, the Kowalish Apparatus Thingy (KAT). He re-familiarizes them with the multitude of levers used to operate the crustacean contraption and introduces the Basic Underwater EQuipment for Recon (BUEQR), a chemo-magical substance that provides breathing and barrier against water. Epi bronzes their weapons to mitigate corrosion from the underwater work and hands their elected leader, Blameless, the scroll of mission directives.
Blameless, exercising his authority as perfunctory leader, announces he will like to kill everyone with the KAT, specifically not excluding his teammates. He unrolls the scroll and reads the single word: Activate.
Levers hum and position themselves to automagically deliver, over the next several hours, the KAT and its R&S occupants to the last known location of the missing Golden Merchant. The disembodied voice of Epi announces over the audio system that they have arrived and the operatives spread BUEQRs all over their faces as well as the KAT rear hatch and shuttered portholes. Silly levers open the forward shutters and they behold the remains and cargo of the Golden Merchant scattered across the sea floor. Some fish men are looting nearby crates and barrels, rudely stealing what R&S has commandeered.
Several fish men riding sharks converge to ram the KAT. A much larger fish man with twice as many arms as the usual fish men arrives on an even larger shark to supervise the ramming. He yells motivationally in sahuagin, a language unknown to the party.
Huck and Fin go to work on the shark fish men with the KAT. Fin batters the sharks with the right claw and Huck grapples the big shark with the left claw. Blameless slings chill touch through the shutters. Silly finds clever ways of conducting shocking grasp through the KAT’s structure into the sharks and riders. The four-arm fish man, whose name seems to transliterate to common as Nhhhhrrrgh!! exchanges testy words with a regular fish man and Nhhhhrrrgh!!’s shark settles the disagreement by eating the other shark and rider whole.
Everyone hears a rumbling over the sounds of underwater battle in the distance, and some boulders fall away revealing a cave in the exact same distance.
The fighting proceeds rhythmically until Nhhhhrrrgh!!’s four arm forearm wristband turns especially green, apparently signaling a quick withdraw because that’s what happens next.
The respite gives Silly the opportunity to tinker with the KAT which has been damaged to the point that lights are out and Epi can no longer coherently fuss at them over the audio system. Silly removes several shark teeth from the KAT’s hull as well as a magical trident [Trident of Fish Command, DMG 209] which she hands over to strong Fin.
There is more distant rumbling and tumbling from the cave, as though it earnestly summons their attention.
Once Silly has the KAT nominally operational, they guide it forward to collect the strewn cargo, hopefully to include the sought unicorn horns. Alas, a patch of algae the KAT walks over rears up and attaches itself to the starboard claw. Fin tries to beat away the algae with the trapped claw and Huck fires bronze tipped arrows into the beast, but martial damage seems only to cause bubble eruptions to detach into new baby algae.
One algae baby enters through the open shutters and attaches itself to Fin, restraining, blinding, and suffocating her. Huck rushes to stab at the algae without skewering Fin, and Fin eventually axes it to death from the inside.
Blameless tries several flavors of chromatic orb on the algae and settles on acid damage, but the algae blight spawn master, as everyone agrees to call the mother algae, absorbs the orbs until Blameless runs out of spells. Silly adds on a ray of sickness and wisely proposes to avoid the algae fields in the future. Blameless magically mends the KAT and they walk out of the algae family patch. The algae withdraws.
Silly, Fin, and Blameless exit the KAT to search through crates and barrels for valuables leaving Huck to unroll his tools and make repairs to the KAT’s furnace. Most of what can be found is ruined foodstuffs, but they do recover a meager collection of coins missed by the fish men and some oil flasks.
The unicorn horns are notably absent from the wreckage so Blameless proposes taking the KAT in to explore the rumbling cave. Being killed by a cave seems a better prospect than returning with a mission failure so everyone agrees.
The inside of the cave looks like an ancient palace. Across the back is a worked wall that Fin’s stonecunning informs her was made by neither man nor fish. A gate in the center is closed by an adamantine chain, allowing individuals to squeeze through but not the KAT. Beyond appears to be an enormous constructed pit with a chest set on the exact opposite side.
Huck locates a weak spot in the gate where time and sea have eroded the bars. Fin leans hard into the hydraulic levers and the one remaining good claw spreads the bars wide. Huck deftly pilots the KAT silently through the hole.
The chest creaks open revealing the unicorn horns. The chest is loaded onto the KAT successfully but the creaking noise has awakened a kraken in the pit. Abundant inky blackness drifts from the pit, challenging the party to escape a horrible death.
Fin leans hard into the forward lever, so hard that the mechanism breaks and the KAT is adrift. Kraken tentacles capture the vessel and pull them toward their inevitable watery demise.
Fin reminds everyone she has a helm of teleportation. As the mission always comes first at R&S, she teleports the chest of unicorn horns back to headquarters while Huck prepares an oil bomb using the oil flasks and oxygen-rich BUEQRs with a twenty second fuse. Blameless continually mends the KAT to slow down the kraken’s destructive crushing, buying Fin the time to teleport back in and out again with her cohorts, saving the day.
Epi reports observing a great explosion burst from the sea, filled with kraken guts. Although in some trouble for losing Epi’s KAT, the mission is hailed as a success.