This article assumes that the characters are not using DDAL06-02 The Redemption of Kelvan as their hook into the White Plume Mountain adventure. Although that adventure is the intended path to get characters involved, the following text can serve as a secondary route to get them here!
“There is something about the North, I think.”
I read the broadsheet from Neverwinter again. The headline was in large block letters, as plain as the rising sun: River of Blood! The article was sensational and graphic nearly to excess; someone had enacted a plan to turn stain Neverwinter River fully red with blood. Bodies were piled so high along the river bank that they reached the street level in some places, it claimed, and the river rocks will be forever stained.
“Utter garbage”, grumbled Durnan. “If y’ask me it was probably just four or six adventurers that ran afoul of the wrong kind of orc grog and fell into the Neverwinter River.” He continued cleaning the chipped steins behind the bar and didn’t bother to look up.
I kept reading, and once the article had extended off of the front page and into the back sections it discussed the accused. An entourage of nobles, led by Sir Bluto Sans Pite from Luskan, have been accused of slaughtering sailors and peasants alike and tossing their bodies into the river. The article didn’t make clear any reason for these actions, though it painted them in a fairly horrible light and included some fairly high-quality sketches of Sir Bluto’s face on the back page. Below the sketch could be seen a whole slew of charges, including murder, extortion, escape from prison, dereliction of duty, assault upon a priest of Ilmater, drunkenness, and more. The gold reward was substantial – 10,000 gold pieces!
“Durnan, some people are just mon-” I was interrupted by a pair of visitors that burst through the door, their voices loud and intermingled but all seemingly intent on confronting the grumpy barkeep.
The first, a brightly-dressed Shou trader named Fai Chen dug deep into his pouches while his words, much like his copper and silver coins, spilled out into the room. “DURNAN! Sir, this injustice will not stand!” he bellowed as he slammed a neatly-folded piece of parchment onto the countertop.
Durnan merely raised an eyebrow and continued wiping his steins.
The second, a thickly-scented wizard with a porcelain mask and deep anger in his eyes, presented a note as well. “My old friend”, and there was much emphasis on the word friend, “it appears that someone has taken it upon themselves to explore our stocks. The trader and I are in identical circumstances. I would strongly suggest that you examine your trophy case.”
At this, Durnan actually gave a start. I don’t know that I’ve seen Durnan look alarmed before, but that certainly washed across his face – he dropped the mug and hurried over to a locked trophy case next to the bar. He gasped, fumbled his keys into the lock, and removed a similarly-folded parchment from one of the shelves. The three of them fell into a hushed conversation and I realized that this was my chance.
Fai Chen’s note was still on the bar, and they were not looking in my direction. I gave in to curiosity and stealthily took it. I covertly unfolded it below the bar and read the contents:
Search ye far or search ye near 
You’ll find no trace of the three
Unless you follow instructions clear
For the weapons abide with me.
North past forest, farm and furrow
You must go to the feathered mound
Then down away from the sun you’ll burrow
Forget life, forget light, forget sound.
To rescue Wave, you must do battle
With the Beast in the Boiling Bubble
Crost cavern vast, where chain-links rattle
Lies Whelm, past water-spouts double
Blackrazor yet remains to be won
Underneath inverted ziggurat.
That garnered, think not that you’re done
For now you’ll find you are caught
I care not, former owners brave
What heroes you seek to hire.
Through might, I’ll make each one my slave
Or send him to the fire.
As I completed my read, the trader paused in his barrage of whispers and cleared his throat. “Feathered mound? You don’t think… there was that fortress that recently appeared, as if constructed overnight by magic…”
The wizard interjected: “Keraptis. Damn him. He can’t be allowed to keep those artifacts; they’re simply too powerful and that’s why they were separated.”
The three shared a look, then as one swiveled to look at me (why the Yawning Portal was empty was a mystery to me; it was mid-day after all). Durnan maintained eye contact as he walked towards me. “You. You there! You look like the adventuring type – you want to make a massive pile of coins, right? Earn a few potential favors from my allies and me? Listen up…”
Spoilers below!
For the DM:
Thinking outside the box: