"Okay. Thank you!"

It sinks beneath the water and swims away.

"Do you know what a 'cycle' is?"

"I've no idea. It won't be a day... how do they even track time down here?"

"In larger groups, there are clerics, of course. I assume you would know if one of the otyughs was empowered. Smaller, some areas have glow-plants of one sort or another, and those often have a fairly regular dimming and brightening period. I haven't seen any in here. Does the sewer system flush or get new water at regular intervals? Could be something like that. The standard otyugh diplomats are on a human schedule, they might provide enough of a clock. Some undead have fear the sun enough to cringe when it's up even if the light is through hundreds of feet of stone, but the sewers shouldn't have many undead. How dense are the sewer entrances? Some of them leak light, and if they're common enough, the otyughs might track when they are or aren't lit. They'd probably miss a day here or there, but that one didn't seem to have anything urgent to do. Some of the waterlife might habitually follow any of those, or some other pattern entirely, and the otyughs can see their travels as a clock. I can go on if you want more options."

"I don't know if any of the otyugh are clerics. The sewer waters don't have any sort of regular schedule I'm aware of. How exactly they keep time doesn't really matter, I suppose. We should continue."

"As you say." It might matter if their cycle time is substantially off from a day! Whether this started a few days ago, a few weeks ago, or just a few hours ago could be important! It's almost certainly a few days. The guard would have heard about it earlier if it was a few weeks, and the exact details of "a few days ago" aren't actually that important right now. Fine.

Navarro follows his map down the deep tunnels. The twists and turns slowly fade into straight passageways. At evenly spaced points, there are doorways in the stone. Some spiral up in staircases, some have lead into long dark tunnels, and some are just holes in the wall, leading to nowhere. What little underwater life is here is distressed, but it doesn't seem to notice them.

They reach a crossroads. Almost fifty feet down one tunnel, Tencednil can see a pair of strange looking wooden barrels sitting on the stone walkway.

She keeps them as up to date as her shadow does on the state of the water creatures. 

"There's something down that way. Barrels, I don't know if they're trapped. A bit out of Light reach from the crossroads, but just sitting on the walkway. I can send my friend to investigate, but is there's a trap it won't see it." Does a Detect Magic show anything?

The barrels are not observably magical.

"Have your friend approach. Carefully."

She nods to it, and it drifts in slowly. What does it spot when it gets within thirty feet of the barrels? Twenty?

There is no life in the water within thirty feet of the barrels. At twenty feet, her shadow can see a doorway in the walls next to them. Inside is a tunnel that slopes upward at a steep angle.

<Nothing moving close.> Drift in...

<Door close! Goes up!> It zoom back and wobbles at her.

"It says the area around the barrels is empty, there's nothing moving in the water. There might still be undead, if they're stationary and blend in with the sewerbed. A little past them, and over in that direction, there's a door along that passage, which leads up. I'd guess out of the sewers, but it's a guess. Is there supposed to be an entrance anywhere near?"

"That would be one of the old commercial access tunnels. None of them should be in use anymore..."

"It might not be in use, but the barrels certainly did get here somehow." Navarro gets to decide whether to approach. He is both the leader and the one most likely to spot anything suspicious about the barrels.

"I'm going to go scout up this place, alone." He turns to face Garril. "If I don't return within ten minutes, leave quickly. The Citadel must learn of whatever this is. You have command."

"If I see something jump at you, do we run or attempt to assist?"

"No. Leave and do not return without a greater force. There may be intelligence behind this mess."

She nods, clearly on edge. (And actually on edge. This was always going to be risky, but this in particular seems risky.)

Navarro slowly walks over to the barrels. He lifts the top off one and peers down intently.

After perhaps a minute of studying the barrel's contents, he disappears into the the doorway.

Five minutes of silence later, Navarro creeps out of the doorway and back over to them. He whispers. "We need reinforcements. There's six of them in there; hooded, in breastplate, armed with battle scythes. Who even uses battle scythes!?"

He pauses to catch his breath. "The tunnel leads up into some cursed place. They've got these huge vats full of the stuff in the barrels. Horrible red gunk. And a painting of a skeletal woman on the ceiling."

"Urgathoans..."

He sighs. "Almost certainly."