Syzygy looks at the scroll in his clammy hands, he then looks at the king. Syzygy channels the scrolls enchantments and directives and attempts to impose his will upon another.

hold person: dc wis 14

King Grol:  DC13 Wisdom Save or be paralyzed: 6.  (I believe the scroll prescribes a set spell save, overriding your usual spell save?)

The King seizes up in the doorway, gasping and grunting, his arms twitching. (Attack rolls against him have Advantage; any attack roll that hits him is a Critical Hit if you're within 5 feet of him.)

Quinn, Bryony, and Jurgen may act next!

Jurgen will cast green flame blade and attack with his sword. (27 to hit for 18 points of damage) 5 point to the one next to him (if 5’)

Quinn draws his battle axe and rushes in after Jurgen. He swings down the battle axe with a two handed grip. He looks up knowing there's one more threat in the room and he backs away into the smoke hoping to hide.

Action: 20 to hit for 11 damage.

Jurgen slashes the king with a devastating blow of his sword. The green flames, however, fail to reach the second, hidden target you know is somewhere in the smoke.

Quinn steps forward next, sinking his battle axe into the paralyzed bugbear's chest before disappearing into the smoke.

King Grol is slain with nary a gurgle. But his henchgoblin still hides in the smoke.

Another arrow flies wildly out of the room, aimed loosely at Jurgen:
 Longbow Attack: 4. Hit: 8 piercing damage.

Bryony and Syzygy may act next! 

The smoke is beginning to clear. ...but not enough to change play yet.

Syzygy pokes his head through the doorframe and brings forth moonfire.

dc dex 14

[and apologies for the previous scroll dc, I thought it only applied to spells above my level + also confused myself because it’s the same spell I chose at level 3 but hadn’t cast yet] 

To see through the smog

perception: Nat 20 for 23.

Syzygy spots the hobgoblin archer in the black smoke, which has begun to clear somewhat.

The hobgoblin gasps and tries to dodge the arcane blue flames descending upon him.
DC14 Dex Save or take 4 radiant damage: 19

Quinn, Bryony, and Jurgen may act next. Roll a DC10 Perception check, first. On a fail, you attack blindly and at disadvantage. (Darkvision does not apply here.)

Jurgen Perception: 20

He will move and attack with his sword (21 to hit and 14 damage) 

Jurgen spots the hobgoblin in the thick haze and impales it with his blade before it can shoot again. It crumples, dead, on the stone floor.

Combat is over. The smoke dissipates further; you can see much more clearly now.

What next?

Jurgen points over at the door in the northwest side of the room. He walks over and listens. 

Investigation 15

Perception 9

Jurgen hears nothing.

Jurgen looks to the party, seeing no objection he opens the door ready to attack any enemies. 

Quinn rushes to search the dead king for keys, items or anything of importance. 

Syzygy will check the fire in case something of interest is being burned. 

Jurgen finds a partially collapsed chamber that was once a comfortable bathroom. It still contains a large tile tub, clearly unused by the castle’s current occupants. Gundren Rockseeker, your dwarven employer from the city of Neverwinter, is here. He is bound and semi-conscious, lying on the floor, muttering. The room otherwise contains nothing but rubble and rubbish.

Quinn searches the body of King Grol. He wears a set of jeweled silver teeth over his own rotting fangs, but they are affixed to him with strong, brown glue. He carries a massive Morningstar, a greasy comb, a few nasty-looking snacks, and nothing more. No keys or other items of interest are with him.

Likewise, Syzygy finds that the brazier contains nothing but sticks and a few small blackened bones.

A map lay on the table. There are no signs of Kimberley nor of the drow.

Jurgen frees Gundren and helps him up as he is able. He explains the situation to Gurden and states how they are still looking for Kimberly and if he has any clues to her whereabouts.

Next he would go to the unopened door to the south. 

Quinn grabs the map and stashes it in his pack and scurries over to Gundren.

“Do you know where they took Kimberly, the tall human cleric? She’s with us.

Are you hurt? Can you run? We have to get outta here.”