Grovalder has a pleasant look on his face. "Ah, of course I know Moop! Loyal servant of Mr. Diamond. He doesn't get out much, I've only met him a handful of times. Why do you ask, is he well? He normally doesn't depart from the Arrow House, as he usually manages the books and daily tasks at the house."

The store bell rings as a women enters, she is carrying a book. "Oh my, Grovalder you have a full house today! I am stopping for a new drama, and wanted to show you this...but tend to your customers first, I will browse while I wait." She move around you all and browses a shelf on the opposite wall of the other patrons.

Brazzak finds the most open corner of the shop that he can and tries his best to stand perfectly still. He's terrified of accidentally breaking something in the shop.

Modron watches and listens to the conversation between Heilamin and Grovalder.  He is also paying attention to the surroundings in case something doesn't seem right: perception 16

"Actually, no, Moop has seen better days than today. He stormed into the inn where we were staying, handed us this medallion, told us to protect it with our lives. Is there anything you can tell us about this?" Heilamin shows Grovalder the medallion, being careful that only Grovalder sees it, and no one else.

Modron...you pay close attention to the conversation and take another look at the three patrons in Arrow's Oddities...after looking closer you can determine that these patrons AND Grovalder are in disguises. These people are not who they seem. 

Heilamin shows Grovalder the medallion. "My, I can say I have not seen such a thing. Looks to be some ancient relic of sorts. Moop has seen better days, what do you mean by this?" 

(I am assuming Modron is close enough to either hear Heilamin or sees them show Grovalder the medallion) Modron when Heilamin pulls out the medallion and shows it to Grovalder, their facial expression shifts slightly. Not enough for Heilamin to notice. But Grovalder's face turns more alert. 

Modron will quickly grab Heilamin's arm and cover the medallion with his hand.  "Put this away"  He looks back at Grovalder "Who are you really, all of you are not who you seem." Pointing to the others in the shop so Heilamin and his companions can understand. "Where is Mr. Diamond, we need to speak to him now!"  he waits but prepares sickening radiance in case they are attacked.

Outside of Arrow's Oddities.  A male commoner approaches the building. He opens the door and the bell rings again as the door shuts closed behind them. The man is being tailed by two adventurers. A short human female with red hair, pale skin, and green eye that has daggers on her hip and a bow strung to her back. She is accompanied by a hulking human with a halberd on their back and large gauntlets equipped to their hands.

Renee and Mackenzie, you begin your approach on Arrow's Oddities after tailing these commoners to this location.

Back inside, the door opens and the bell rings a second time. A commoner male enters. The small bookshop, which was already cramped with books and the likes, is near it's capacity. When the man enters, Grovalder ignores Modron's question and looks to the man. "Ah, welcome to Arrow's Oddities! Looks like we have plenty of business, yes?" The man nodes in response and looks around the room at you all. Grovalder continues "Well fair travelers, I am sorry, but I cannot be of more assistance. We have work to do...we will be taking that medallion, which that damn goblin kept away from us. We can't have anyone..." He looks at you all. "get in our way."  Grovalder yells "Get them boys!"

When Grovalder finishes, his body starts to twist unnaturally. His body begins to grow amber and black fur, his hands turn to large paws with razor sharp claws, and his face turns beast like with a maws like a big cat. He resembles a jaguar but still holds a humanoid form. The four commoners in the bookshop shed their disguise and are revealed to be more of the cloaked figures. They draw their weapons, combat has started, roll for initiative! Modron, since you prepared a spell before combat, you will be able to use it before initiative. Go ahead and handle that action first, then your next action will be your turn in initiative order. 

Initiative rolls:
Brazzak: 6
Heilamin: 11
Modron: 18
Mackenzie: 2
Renee: 5

Grovalder: 18
Cloak 1: 6
Cloak 2: 20
Cloak 3: 8
Cloak 4: 22

Round 1 - Initiative Order
Renee
Brazzak
Cloak 4
Mackenzie
Cloak 3
Grovalder
Cloak 1
Modron
Cloak 2
Heilamin

Renee and Mackenzie, you can hear a man yell "Get them boys!" A fight seems to have broken out inside of the shop. The windows are shuttered and the door is closed, but you assume it is unlocked. You do not have sight on anyone inside. The front door is 20 feet away from you both. Renee, you have first action (following Modron's spell).

Everyone else, you are practically within 5-10 feet of...well, someone! The only enemy not within 5 feet reach is Grovalder, as he is behind the counter. 

CON saving throws for enemies

Grovalder: 7
Cloak 1: 6
Cloak 2: 8
Cloak 3: 18
Cloak 4: 16

Renee looks over at Mackenzie. "Well, that doesn't sound good. Shall we?" She doesn't wait for an answer as she goes to the door. Renee pulls a small fuzzy object from her bag of tricks. She opens the door and throws it inside, where it lands an ape appears (rolled on discord). If there is room inside she will stealth 16 and slip in behind the creature.

The ape attacks the werejaguar with its fists. The left swing for  16  for 6 damage and the right20 for 4 damage. Both bludgeoning. 

As a reaction Modron casts a sickening radiance spell centered on his current position and using his sculpt spells capability he will make his team immune to the spell (there are at most 5 of us and we are all immune as sculpt spells allows 1 + spell level which is 4, to be immune essentially).  Everyone else in a 30 foot radius must now start feeling the effects.  Those who fail the DC 14 con save take 31 radiant damage at the beginning of their turn and take 1 level of exhaustion.  This will continue until the spell ends, each turn making con saves (I assume I will reroll damage each turn.)

I'll use the rolls above on their turn. For the sake of it...we will say Renee and Mackenzie are sculpted from the spell effects. 

The red head cracks open the door and throws in a fuzzy ball. It hits the ground and rolls around. All of the sudden an ape bursts from the tiny ball, bangs on it's chest, and jumps on the counter to attack Grovalder (werejaguar). Both attacks hit dealing 17 damage. 

Brazzak, you're up with Cloak 4 on deck. 

Roaring a draconic bellow, Brazzak lays into two cloaks.

Quote from Jilguera >>

Renee looks over at Mackenzie. "Well, that doesn't sound good. Shall we?" She doesn't wait for an answer as she goes to the door. Renee pulls a small fuzzy object from her bag of tricks. She opens the door and throws it inside, where it lands an ape appears (rolled on discord). If there is room inside she will stealth 15 and slip in behind the creature.

The ape attacks the werejaguar with its fists. The left swing for  21  for 8 damage and the right22 for 9 damage. Both bludgeoning. 

 Mackenzie opens his mouth to answer, only to close it again when he realises that he would be talking to himself, instead pulling his battleaxe from over his shoulder before charging after the rogue, shield arm leading, reacting instinctively to the threat implicit in the statement "Get em boys", announcing his presence as he storms into the shop with a commanding "Bow to my blade" before swinging once at the nearest Cloak, then again if it is still 'standing' or move to the next nearest if the first goes down, seeking to position himself within 10ft of Renee (if he can still see her) and the strangers that are being attacked

 Note: Mackenzie's imposing presence comes with Aura of Protection granting friendly creatures a +3 bonus to any saving throw if they are within 10ft 

Potential Bonus Action

Cloak 1 and 2 are slashed by Brazzak, but still standing.

Cloak 4's turn and fails their CON save for Sickening Radiance and falls before they can even act! 

Mackenzie enters the building and swipes at cloaks 1 and 2, striking them both down with their halberd! They fall to the ground, dead. Mackenzie bonus action attack on cloak 3 is a criterical hit for 8 damage! They still are standing. 

Cloak 3 moves up within 5 feet of Mackenzie and attacks with it's shortsword.

Cloak 3: Attack: 19 Damage: 3
Cloak 3: Attack: 21 Damage: 4

Grovalder, turned into a jaguar humanoid, swiftly jumps up on the counter next to the ape and retaliates against the beast. If any of the attacks down the ape, they will attack Modron , still standing on the counter.

Werejaguar bite: 10 Damage: 9
Werejaguar claw: 23 Damage: 9
Werejaguar claw: 21 Damage: 7

Cloak 1 is dead, Modron you're up! Heilamin, cloak 2 is dead so you're on deck. 

 All three hit, (needs all three attacks) taking down the ape.

Sickening Radiance continues and Modron casts Blink in order to avoid some of the violence if possible.

First Blink roll: 3 Modron does NOT blink away

Modron attempts to move outside or as far from the enemies as possible without creating an attack of opportunity (hard to know without an exact map so this is up to the DM.)

You would be moving past the werejaguar as they were in range to attack you from the counter, taking an opportunity attack if you do so.

Modron will risk one attack of opportunity if he can then move away from the difficulties (his movement is 25 feet.)

Werejaguar opportunity attack:27 Damage: 14

As you step away you are bitten by the werejaguar standing on the counter and take 6 damage. Heilamin, you're up!