"Because my dear we have bigger fish to fry right now." 

Dabbledob places her hands on her hips for emphasis.

 "Bigger than a dragon?"

 "Ha! Size is not everything." Fibblestib shakes his finger.

 "Well then perhaps we can help with your big problem?"

Elandra forces a smile, "and exchange you can help us out with our small one?"

 Again the gnomes whisper amongst themselves for a moment.

At last Fibblestib steps forward tucking his hands behind his back as if to start a lecture to a bunch of students. He looks up at them all with a serious eye.

"You may or may not know that Gnomengarde has two married kings who rule in tandem — Gnerkli and Korboz." he waits for confirmation but when none is given he continues with a nod.

"King Korboz recently lost his mind and is keeping King Gnerkli as his prisoner. It is a strange and worrying affair and has gone on far too long."

"We don’t understand the nature of Korboz’s affliction, and are at a loss as to what to do. We wish no harm to befall either king!" he pauses here for emphasis.

"...but King Korboz has become a danger to himself and others and if you can find a way to clam him and resolve the situation then we would be extremely grateful."

A 10-foot-high ledge overlooks the room, set with a wooden pedestal on which sits a leather-bound book.

 "Grateful enough to let me take a look at that spell book?"

Toot points toward the book, instinctively knowing it for what it is."

 "I am sure that could be arranged yes." agrees Dabbledob.

 "Well then. Lead us to their majesties good gnomes and we will see what can be done."

 The gnomes agree.

They lead the party westward up a narrow stairway and then right through a winding corridor to the King's Bedroom.

Outside of the Gnome Kings’ Bedroom

 Dabbledob knocks on the locked door.

"Sires we have visitors from Phandalin."

"Send them away!" comes a voice from within.

 "Sire we have been sent here by the Lord of Phandalin himself to help you."

Deception 13

"Why should I believe you?" comes the reply.

 Thomas places a hand on Anders shoulder. "Go on lad." he whispers.

Casting Guidance.

 "...because why else would we be here?"

Deception 11 + 1

"Could be for any reason! I don't know." 

 "Sire we really need to understand what is going on here so that we can help you."

Persuasion 19 + 2

There is silence then for almost a minute, followed by the muffles sounds of footsteps approaching the door.

A whispered voice sounds from the other side, "I am not opening the door. It is not safe."

 "That is fine. Can you just assure us that the other king is safe... can we please hear his voice your majesty."

Persuasion 10 + 2

"No! Absolutely not!" 

 "Very well your majesty. That is fine, just tell us what troubles you."

"There is a shapechanger in our midst!"

 Anders looks to Thomas with raised eyebrows but the Cleric urges him to play along.

"How... how do you know this your majesty?"

"...because it tried to kill me! It was disguised as a rug in the throne room! My beloved saw it too. He would tell you, but he is foolish and brave so I must keep him safe. It took the others too I know it."

 "What others?"

"Orryn and Warryn, they have been missing for ten days now. Lost to the belly of that monstrosity no doubt."

 Anders looks to the two gnomes with them and they shrug and nod in agreement.

"We will seek out the shapeshifter and return with evidence of its demise!"

The party walk back down to the workshop to discuss next steps.

 Fibblestib pulls out a map of the settlement and spreads it on the table.

He points to a spot at the back of the throne room. "There is a secret entrance to the King's bedroom behind the thrones. Korboz had forgotten it in his madness it seems. You could enter there and subdue the king?"