[Assuming Danica and Nalomanterys have no burning desire to fight plants...]

The party quickly moves back from the greenhouse.  The plant monsters inside strain and reach towards them, but are either unable or unwilling to venture forth from their soil.  Continuing south, the party uses the cover of the rainstorm to approach one of the shrines described to them by the kobolds.

The party approaches from the north, which appears to be the rear of this shrine.  A ruined domed building at the heart of this compound, surrounded by a mostly collapsed wall. Tall monoliths flank the entrance on the far side, decorated with images of a jaguar with six snakes sprouting from its shoulders. 

Before you, a rotten, overturned cart lies beside a pair of animal corpses.  They look to be an amalgamation of jaguars and serpents.

[Those of you who participated in watching the gladiator fights back in Port Nyanzaru would recognize these creatures as kamadans. ]

Before you can investigate further, a chirping cry erupts from the ruins around you, as small, colorful frog creatures spring their ambush.  Danica, Meili and Mica [passive perception greater than 14] notice them just in time, but Ran, Nalomanterys and Eligos are caught by [Tooltip Not Found].

Most of the creatures are atop the wall [10' up], on the roof of the ruins or in the trees [15' up] but a few are on the ground, peeking out from behind cover.

Initiative:

1. Danica
2. Mica
3. Ran  Surprised
4. Nalomanterys  Surprised
5. Eligos  Surprised
6. Meili
7. Grung

Meili did notice the creatures in time but hesitated to attack. No, she remembered "The Book" well enough to understand that the cute colourful frogs are in fact poisonous aggressive territorial creatures Volo called "Grungs". Except, they did not attack yet.

"Remember about their poison! They use it on the weapons too."

She tried to keep in view as many grungs as she could so at the first aggressive move she would throw the boomerang at the attacker.

Attack: 19 Damage: 7

Mica pauses as they approach the shrine, spotting the frog-like creatures at about the same time they spotted him.  He quickly nocks and arrow brings his bow up to the low ready, but pauses before taking a shot. He calls out warily “We aren’t looking for any trouble.  We just want to pay our respects at the shrine. Can we pass?” 

Ready action to attack the creatures on the roof of the shrine if they attack the party first.

Attack: 18 Damage: 5.

Attack: 7 Damage: 3.

.

Shaking her head as they walk away from the greenhouse, she had to agree with Mica's words of confusion regarding the greenhouse's purpose. But they could worry about such trivial mysteries after they truly ended the death curse and survived. Seeing the two dead predators immediately put Danica on guard and her hairs raised as she, Meili and Mica spotted colorful small humanoids in the brush but a moment before they began to emerge. Their cry seemed fierce in their own way...yet they didn't pounce. 

Not taking her gaze off of their would be ambushers, she heard out Mica's words and just in case it would help and perhaps one of them were more in touch with the druidic arts, she repeated what Mica said in Druidic as well, stepping very slowly closer towards Meili and coincidentally a smidge closer to the pair in the trees as well. Readying herself to cast Thorn Whip on the closest Grung should any of them attack. 

(Oh! Forgot the second attack on my Ready Action: Attack: 25 Damage: 8)

[Actually, extra attack reads, in part...

"...you can attack twice, instead of once, whenever you take the Attack action on your turn."  [Bold emphasis added by me.]

Since your readied Attack actions use reactions to attack during another creature's turn, Extra Attack doesn't apply.  If that changes what any of you would like to do, please feel free to change your action.

Also, if #2723 did not make it clear, these creatures appear to be attacking you from an attempted ambush.  They do not appear to be pausing for dialog.]

Then consider Meili attacking right away a green frog to her left.

Since they don’t look like they are in the mood to talk, Mica targets the orange one on top of the building.

Danica will target the one closest in the trees with her Thorn Whip but unfortunately rather spectacularly miss. (Nat 1 for total of 7 to hit)

As the creatures emerge from their ambush, brandishing bows and spears, Danica and Meili respond by attacking the green Grung in the nearby tree.  Meili thunks one of them hard with her boomerang, which immediately returns to her hand, while the Grung rubs its head in pain.  Danica slings a rope of thorns at the other, but manages only to snag a tree branch.

Mica, meanwhile, plants two arrows in the bright red Grung on top of the building.  It ribbits loudly in protest.

While Nalomanterys, Ran and Eligos are too surprised to react, the Grung spring into action.  

The Red-skimmed Grung on the rooftop waves its spear over its head while it inflates thin-air pouches on its neck, croaking loadly.  All around the party, in a 20' radius circle, the plants begin to grow and change, sprouting long, hooked thorns.  

[The green circle area becomes difficult terrain for the duration. When a creature moves into or within the area, it takes 2d4 piercing damage for every 5 feet it travels.]

The other Grung croak out a chorus of cheers and then attack.

The two Green-skinned Grungs in the tree jump down to the ground and draw daggers dripping with contact poison, targeting their attackers, Danica and Meili:

Poisoned Dagger Attack on Meili:  13

Poisoned Dagger Attack on Danica:  9

Luckily, both attacks miss.  

Along the western wall, another Green-skinned Grung jumps down and hurls a dagger at the surprised Ran.  Next to him, a Yellow-skinned Grung knocks and arrow and fires it at Ran.

Poisoned Dagger Attack on Ran:  8

Poisoned Arrow Attack on Ran:  25  Piercing Damage:  9  Poison Damage:  12

Atop the roof, two Green-skinned Grungs hop closer to the edge and throw daggers at Mica, while another Yellow-skinned Grung sends an arrow at the Genasi ranger.

Poisoned Dagger Attack on Mica:  22  Piercing Damage:  4  Poison Damage:  7

Poisoned Dagger Attack on Mica:  18  Piercing Damage:  3  Poison Damage:  3

Poisoned Arrow Attack on Mica:  14

Finally, from behind the overturned cart, another Grung rises, Orange-skinned and larger then the others.  It chirps loudly and then jumps 25' closer, drawing its bow and firing an arrow at Meili.

Poisoned Arrow Attack on Meili:  22  Piercing Damage:  4  Poison Damage:  3

The entire party is back up before the Grungs can act again!

Seeing how quickly things were going south with this ambush, starlight bursts from Danica's chest as she takes her Starry Form, the constellation of the Chalice swirling on her torso as she surveyed her crew's injuries. But she focused back on the same green Grung that had hopped down from the trees and and tried to attack her and Meili. Throwing her hand out, another thorny vine sprouts from her palm and whips towards it. She was trying to take advantage of the pointed terrain that had sprung up around them by dragging the amphibian over said ground and get it closer for her to hit without having to navigate the treacherous terrain herself. "If we kill that red frog, the spell should drop." The elf advises. 

Movement: None
Bonus Action: Starry Form - Chalice
Action: Thorn Whip (14 to hit, 5 damage)

Danica's Thorn Whip grips hold of the Grung, pulling it 10' closer to her... which means 10' of dragging through the thorny vines.  By the time the creature arrives at its final destination... it has become its final destination.  The Grung drops limply, torn to shreds by the thorns.

((Are those hexagons 5' or 10' across?))

Using "Deflect Missiles" (it's more than 4 or even 7) and since damage will be 0 (zero), spending 1 ki to catch the arrow and make a ranged attack against the same green frog (red is too far for this kind of attack):

Attack: 12 Damage: 6

Does Meili still get poisoned in this case?

[Ran - hexes are 5’.

Meili - no poison.  If the arrow never hits her, the poison damage doesn’t happen.  Also, to be clear, this injury poison does not apply the POISONED condition, it is just poison damage (for now). ]

Meili deflects the arrow from the Orange Grung and sends it on a new path to the other nearby Grren Grung.  The arrow pierces its bulbous eye, and the little frog falls.

[Both Green Grung near the tree are dead.]

As hooked vines suddenly sprout and wither under his feet and poisoned darts rain down around him, Nalomanterys finds himself too stunned to act. When he regathers enough of his loose wits, he instinctively casts sleep (first level) on the 3 remaining (I think) Grungs on the roof. "Dormio!"

Sleep HP: 24

Then the wizard drops prone with his hands covering his head. (should give disadvantage on ranged attacks against him).