Bow follows the rest towards the drumming, on the way he makes sure his bow is in his hands.

(How far does the drumming seem?)

"Let's try to be quite and see if we can find out what is happening before encountering what ever it is." 

Stealth: 22

You all come to the edge of a clearing, but by remaining back and taking advantage of the trees, bushes, and shrubs you are not noticed by the natives.

There are only 3 on the opposite side of the clearing and they are the source of the drumming as each are playing a set of bongos. They wear simple, handmade clothing and 2 have a crude stone axe secured at their waist, while the last has a pouch.

In the very middle of the clearing is a 10 foot diameter hole in the ground. Spread out around this hole are a half dozen strange flowers. They are medium sized and end in a blossom of dark purple petals. They slowing sway back and forth in a sinuous motion and occasionally emit a little spray of light purple mist which hangs in the air briefly before being drawn down into the hole by a natural reverse draft.

The clearing itself is more of an oval than a perfect circle, being 60 feet from you and the natives, but only 45 feet wide.

Randall:

Watching carefully, Randall scans the area for any more clues of what is going on here, and he tries to understand why the natives are drumming—are they influencing the strange plants with their drumming?  Perhaps there is something in that pit they are trying to drug with the plant’s emissions?

Perception:  25

Insight:  24

The flowers seem ominous. Could the drums be some ritual to placate some form of creature? Surely there must be more natives around as well. 

Perhaps we should send a couple of non-threatening (high CHA) party member in to parley with the rest of the party hidden and ready to pounce if it turns violent. 

Z instructs Irraxan to turn itself invisible and scout around the periphery of the clearing (near ground and also from higher in the air) as well as behind the drummers for more natives. He instructs Irraxan to stay well clear of the flowers for the time being.

It is such a strange scene unfolding before you... did the plants come out of the hole and are now being held at bay?... is the mist drugging the natives to play music for the dancing plants?...

Even with such a high roll the entire thing is beyond odd and beyond understanding without further interaction. The one thing you know for certain, the drumming and the plant's movements are connected in some way. Also, the natives wear peaceful expressions on their faces. No fear or anything else, just intent and dedicated to playing their drums.

Irraxan doesn't spot any other natives nearby but can easily see a well worn footpath from the air. It begins behind the natives and leads away from the clearing.

Irraxan is to follow that path, remaining invisible. Also still in crow form (just in case something has ability to see invisibility but not actual true sight)

Petcan gestures for everyone to wait, and he moves forward into sight of the drummers. He doesn’t interrupt, yet. Just moving forward to be acknowledged, and watching for anyone else who might be around. 

Keep about ten feet between himself and the flowers. 

Randall:

As Petcan starts to move out, Randall taps him on the shoulder as he goes, saying, “Lightbringer be with you.” (Guidance).

Tempe looks upon the scene and thinks upon the plants and the people nature 21

Bow imbues his handbow, you know, just in case.

He takes 2 damage.

Irraxan flies off following the path.

When Petcan steps out into the open the native with the pouch stops drumming, stands and points toward the plants. She speaks clearly and loud, "Beware the Purplewrath!"

As Petcan moves forward, keeping a good 10 feet between him and the strange plants, one of the plants turns it's bulb towards him. The next second it rushes toward you and engages in melee.

(Gonna try something a little different for initiative. Each player will start their post with an initiative roll and then post their turn for round 1. When all 5 players have posted their turns I will do a brief summary for round 1, and call for round 2 to begin.)

(Everyone is up. Roll initiative and make your post for your turn in round 1.)

Petcan initiative 7 

Petcan sees the aggression and heaves a great breath and when he breathes out, a great wall of fire appears around the flowers 

The inside of the wall is the damaging side. Anything within 10 feet has to succeed on a DC 15 Dex save or take 23 fire damage. Anything that ends its turn inside the wall or passes through it, takes 19 fire damage (no save). 
edit for clarity: targeting around the hole, including the flowers

Randall:

Seeing the situation getting rapidly out of hand, Randall considers trying to magically end the conflict but realizes his spell only works on humanoids.  Sighing, he hopes that focusing on the plants will give them a chance to negotiate with the natives.

Invoking his Spirit Guardians, Randall moves up next to Petcan and draws Lightbringer, preparing to receive any incoming attacks.

Spirit Guardians:  DC 16 Wisdom or Radiant Damage within 15':  10

Initiative:  1

Tempe "We are supposed to make allies!" he says as he produces a flame on the tip of his tongue and flies up in the air 

"Stop this," he forcefully shouts Intimidation 15 at the natives.

@Randall

Don't forget to roll your initiative for your turn during Round 1. It will determine in what order your turn takes place.

9 Initiative

Z casts [spell]Blight[\spell] on the plant. Save: CON 14, at disadvantage. Damage is maximised against plant creatures and magical plants, so 8d8 = 64 damage; or half if it saves. 

He then uses his flying speed (boots) to move into the air and out of reach, on the assumption that plants can't fly to engage him in melee or grapple him.

Bow initiative:15

(if it seems the native is controlling the plants bow will use blood curse of the muddled mind to give it disadvantage on con saves, if it doesn't seem to control them nevermind :P)

Than he attacks either the native if it controls the plants or the plants of the native doesn't control them

Attack: 24 Damage: 20

Attack: 20 Damage: 23

Bonus Attack if muddled mind was necessary for the native: 18 Damage: 25

Native's Initiative: 3 

The natives point at the plants and scream in their strange language, then any who live turn and run along the footpath.

Purplewrath's Initiative: 12 

The plants rush through the ring of fire and try to attack anyone they can reach.

(will roll their attacks when I know if any survive)

Round 1 Summary

17. Tempe flies up into the air casting a cantrip and shouting for the natives to stop this hoping to intimidate them to cease any hostilities.

15. Bow unleashes 2 bolts and slows one of the Purplewraths to barely a crawl as it appears severely wounded.

13. Petcan's ring of fire appears around all 5 of the Purplewraths and they suffer 27 fire damage as they rush through the wall, the one with 2 bolts in it collapses dead in it's tracks.

12. The 4 remaining Purplewraths converge on Petcan and each make 2 attacks.

1st Attack: 20 Damage: 5 

2nd Attack: 21 Damage: 9 

3rd Attack: 25 Damage: 10 

4th Attack: 21 Damage: 8 

5th Attack: 6 Damage: 7 

6th Attack: 18 Damage: 9 

7th Attack: 17 Damage: 6 

8th Attack: 15 Damage: 5 

Petcan also needs to make 4 CON saves vs. DC 12 or be blinded by the purple mist.

9. Z casts blight and one of the Purplewraths dries up into a wrinkled husk, dead. (it's save is irrelevant as even half damage would kill it at this point)

3. The natives scream and point at the plants before running off.

1. Randall moves to stand beside Petcan casting spirit guardians.

1st PW's save: 9 

2nd PW's save: 2 

3rd PW's save: -1 

Randall also needs to make 4 CON saves vs. DC 12 or be blinded by the purple mist.

(Everybody is up. Roll initiative for Round 2 and include it in your post for your round 2 turn.)