Rel stands where she is, hoping to be the anchor binding together the separated party.  Continuing to scan for any approaching threats.

"We still have at least another floor or the manor to investigate as well, and I think we should," she observes to those still within earshot.

Bellamy

 Lana

"Its mostly overgrown weeds, but I could have sworn a plant was moving. Lets close the door for now until Lana comes back" says Bellamy. He then closes the door and head back into the room with the others to see what Lana found

Tex follows Bellamy, “Any news from Lana?” He asks Zane. 

Lana made a few steps forward - no more! - just to assess the layout of the place as best as she could (Perception: 15), then looked around the stairs, if there were any footsteps proving someone was using them (Survival 5), and finally climbed back.

"There is a huge cavern down there. Heard water running somewhere deep. I bet there are passages running for miles under the city. And who knows, there can be more secret entrances into that cavern from other rooms. If so, the house is just a decoration. No wonder no one came to us even after all the noise we made." She pulled up the ropes and began to fold them but then stopped. "Want to check it out or should we first finish searching the house?"

"I would like to finish searching the house as we may find ourselves unable to come back." says Bellamy

He then shares what he saw in the other room and how he thinks a plant was moving

Zane nods, "Yeah, let's finish searching the house. At least we know to mention this tunnel to whoever comes demolishing it tomorrow. Let's move a couch on top of this for now so that nobody can come crawling out while we're elsewhere."

"If there are plants moving unnaturally beyond that door, I suggest we kill them at range.  I am sick to death of enemies lurking as apparently harmless objects, only to come to life and attack us by surprise.   I believe I can clear the area of danger with my Eldritch Blast without risking setting the entire property on fire as might happen with Bellamy's Fire Bolt and without wasting actual arrows or bolts.  Agreed?"

IF all are in agreement, Rel approaches the door to the overgrown area, makes sure everyone is in position to defend against any hostile plants, and then spends several minutes spraying the entire area with her black beams of energy, starting with all plants near the area that Bellamy saw movement.

(Unlike Fire Bolt, the description of Eldritch Blast indicates it only harms creatures, not inanimate objects.  Rel will kill every non-tiny plant or other creature in the area.  Again, only IF all are in agreement with this brute force precautionary step.)

"Agreed lets kill the moving plant. I will stand by in case backup is needed" says Bellamy

Tex nods in agreement and takes position in the front line with Liz at his side. “Desperate times call for desperate measures, I guess.” Tex also keeps an eye out, with Lizzy’s help, for anything that moves and tries to hide.

(Perception: 20 [help 9])

"You sure? I can just lock the door again." But since her shooting was not required here she just shrugged and followed others taking this time as a break.

Tex lights a torch, while Rel bombards the flora, and waves it menacingly for any potential plant-based threat to see, “Shall we have a look around what might be… ahem… left in there?”

Rel tries to identify the moving plant Bellamy had noticed and target it with her black beam first.

Eldritch Blast at disadvantage, to hit:  14
Eldritch Blast damage on a hit:  7 (force)

To Lana, she replies, "true, if we do not wish to search the greenhouse, we could just lock the door behind us.  My thought was we need to search every location in this manor, in case the coffin or any other object of interest might be hidden within."

"Hm... Objects of interest so far were quite interesting, can not argue with that. You know, maybe we can lure those plants of yours into the open. Let me be the bait."

If the group was set on eliminating plantlife in the greenhouse, Lana walked in and looked around searching for the enemy and pointing one should she find it to the others. Should she spot something else, she would shout it too.

(Perception? 24)

As your discussion unfolds, Rel launches a frustrated beam of eldritch energy towards the plants, in hopes of striking whatever 'thing' that Bellamy saw moving. Her blast strikes a plant harmless plant, causing it to wither and turn black, practically turning to ash. As this happens, a mound of rotting vines, weeds, and decaying roots rises from the greenery. Groaning as it sheds dirt from its leafy appendages. You look upon this large monster as it begins to lumber towards you. 

Tex firmly holds his spear as he prepares to defend himself against the monster. He stands right in front of Rel a few steps int the greenhouse with Liz just next to him. His intention was to defend the exit of the greenhouse so that anything that wants to leave must go through him. 

(Zane dropped the silence after both directions were investigated)

Zane spots the thing moving and says "Bad compost!" (vicious mockery for 1 damage).

He then backs away 15 feet (west) to make room for others. "It's probably pretty slow, so lets try to destroy it from afar and back away as we do."

He notices Tex twitching and says, "Right, Tex?!"

Tex listens up and prepares to retreat outside the greenhouse and into the corridor with Liz leaving first and Tex covering the backwards movement. "Right, right," he responds to Zane while preparing to shuffle backwards (at his initiative turn).

Things got interesting pretty fast and Lana did not have to execute her plan. Instead, she joined the plant-hunt. The "bad compost" was properly marked and ready to be shot at.

Crossbow: Attack: 10 Damage: 8 (piercing) + 2 (HM, piercing) + 4 (psychic)

 EoT

Bellamy chucks a fire bolt at the plant monster

Hit: 25 Damage: 1

He then moves back to keep a distance from the monster.

End of turn