U NDERGROUND RIVER
The underground river on this level is swift and loud. Crea-
tures within 20 feet of it are deafened by the roar unless a
soundproof barrier or a silence spell blocks the noise. Any
creature that starts its turn in the river and isn't anchored
must make a DC 15 Strength saving throw. On a failed
save, the creature is swept 60 feet downriver; on a success-
fu l save, the distance is halved to 30 feet. The river flows
just as strongly through area 12 as it does elsewhere.Creatures can walk along a stone ledge that hugs
the perimeter of the dynamo. The ledge is 1 foot above
water level, and four arching wooden bridges span the
troughs near the central hub (area 12c). These bridges
are securely bolted to the floor. The ceilings above the
water collectors are domed and vary in height. The con-
necting tunnels between the collectors and the bridges
have flat, 15-foot-high ceilings.
All doors leading to this area are made of stone and
sealed with Qualith door locks (see "Qualith Door
Locks," page 222). Unless they are held open, the
doors automatically close and lock.
12A. SOUTH WATER COLLECTOR
The ceiling in this chamber forms a dome 20 feet higher
than the floor around the cistern, which is 10 feet deep.
Water pouring in from the east travels north along a
trough that leads toward area 12c.
12B. EAST WATER COLLECTOR
This area is watched by the ettins that lurk in area 12h.
The ceiling in this chamber forms a dome 20 feet
higher than the floor around the cistern, which is 15
feet deep. Water pouring in from the south travels west
along a trough that leads toward area 12c. Excess water
flows north through a submerged tunnel blocked by a
IO-foot-diameter, circular iron grate that Tiny creatures
can slip through. Forcing open the grate while fighting
off the current requires a successful DC 30 Strength
(Athletics) check.
12c. CENTRAL HUB
The ceiling in this chamber forms a dome 40 feet higher
than the floor around the cistern, which is 20 feet deep
and fed by a submerged tunnel to the southeast. Water
also pours in from 10-foot-deep troughs to the south and
east, and forced westward and northward along troughs
that lead to areas 12d and 12e, respectively.12D. WEST WATER COLLECTOR
The ceiling in this chamber forms a dome 20 feet higher
than the floor around the cistern, which is 30 feet deep.
Water pouring in from the east exits through a sub-
merged tunnel in the north wall of the cistern, 20 feet
below the water's surface.12E. NORTH WATER COLLECTOR
The ceiling in this chamber forms a dome 20 feet higher
than the floor around the cistern, which is 40 feet deep.
Water flowing in from the south and west exits through
a submerged tunnel in the east wall of the cistern, 30
feet below the water's surface.Two dead grimlocks float in the cistern, with the
brains torn out of their skulls. This is where the mind
flayers dispose of creatures they feed on. Eventually, the
corpses sink and get swept downriver.12F. DINING EXPERIENCE
The stone door to this room is soundproof, airtight,
and sealed with a Qualith door lock (see "Qualith Door
Locks," page 222). The ceiling is 10 feet high and flat.
The room contains the following features:
Grimlock. A stunned male grimlock is slumped in one
of three stone chairs that face the door.
lllith ids. Two mind flayers are present. One stands be-
hind the grimlock, feasting on its brain while telepath-
ically communicating the experience to the second
mind flayer, which looks on.
Dining on brains is a spectator event for mind flayers.
With the aid of telepathy, the diner can convey the plea-
sures of a meal to other illithids in range. These mind
flayers don't like being outnumbered. They try to stun
as many characters as possible, then gather reinforce-
ments from area 12h.
Most of the grimlock's brain is consumed by the
time the characters arrive. Short of a raise dead spell
or similar magic, there's no way to save the creature
from its fate.12G. CONTROL ROOM
The stone door to this room is soundproof, airtight,
and sealed with a Qualith door lock (see "Qualith Door
Locks," page 222). The ceiling is 10 feet high and flat.
The room contains the following features:
Extremiton. In the middle of the room, the ulitharid
(see appendix A) sits on a swiveling crystal throne
shaped like a cocoon. The throne's base is shaped
from a dark, alien metal. Dozens of thick copper
wires connect it to plates of a similar metal bolted to
the floor.
Crystal S creen. When the characters first arrive, the
throne faces the room's curved back wall, which has
rows of pale white crystals embedded in it. These
crystals project the flickering, spectral image of the
Yawning Portal's taproom, as seen through the eyes of
its proprietor, Durnan.
Extractor Staff. A thin crystal stand near the throne
holds a black metal staff shaped like a warped, alien
spinal column. This is Extremiton's extractor staff (see
the "Ulitharid" entry in appendix A).
While seated in its crystal throne, Extremiton is psy-
chically linked to the psipods in areas 14 and 15 and is
maintaining its Waterdeep simulation (see "Alterdeep,"
page 229). If it leaves the throne, the simulation deac-
tivates and the psipods shut down. When this happens,
the mind flayers in areas 14 and 15 make their way here
to find out why the ulitharid ended the simulation. It
takes them 4 rounds to arrive.
Extremiton has enough on its mind without battling
adventurers. If cornered here, it tries to negotiate a
peaceful settlement. As a lawful evil creature, it tries to
uphold its end of any agreement while twisting a badly
worded deal to its advantage. Primarily, Extremiton isLEVEL 17 I SEAD.E.EPS 227