The floor is not a floor. It is ninety-six bronze-edged plates, each one the width of a stride, and each one sitting a finger's breadth proud of its neighbours on a spring you can hear when you lean on it. High on the north wall a balance beam the length of a boat hangs level, with a pointer at its centre and a bull's head cut into the stone behind the pointer.
Three iron rails cross the room. On each rail stands a bronze ox, cold, head down, waiting to be told.
DM summary. A scale the size of a room, built to admit a bull and nothing else, and the party has to convince it that they are one. Get the weight and the cadence wrong twice and the calibration weights — three bronze oxen — come off their rails to do the weighing themselves.
Terrain & Features
Battle map: The Hall, West End — page 29, 55 × 75 ft (one half of The Great Hall)
The chequerboard is the scale: its squares read as the 12 × 8 grid of sprung plates at 60 × 40 ft. Draw the fixed apron inside the south-east door and the beam gallery as a ledge line along the north wall.
- Dimensions. 60 ft × 40 ft, ceiling 25 ft. The party enters at the south-east corner, on a fixed apron of stone 5 ft deep that is not part of the scale.
- Light. Bright within 20 ft of each of the four corner mirror-lamps, dim in the middle of the room. The lamps are fixed and cannot be carried off.
- The plates. Ninety-six 5-ft plates in a 12 × 8 grid, each sprung. Standing on one is safe; the scale measures the whole floor at once and does not care where the weight is, only how much and how often it moves.
- The beam and the pointer. A bronze balance beam in a gallery 15 ft up the north wall, plainly visible from the door. The pointer sits at the bull's head when the floor carries the correct load. Everything the puzzle needs is readable from here — nobody has to climb to solve it.
- The rails. Three iron rails run east–west at 10, 20, and 30 ft from the south wall. Each carries one Bronze Ox. A rail is a charge lane: five feet either side of it is the only ground the oxen can threaten.
- The sledge alcove. A low recess in the west wall holds a maintenance sledge, a coil of rope, and eleven dressed stone blocks of about 100 lb each. This is the intended non-automaton solution and it is meant to be found.
- The gate. The north gate is a bull-head lock whose bronze tongue drops out of its slot when the beam balances, and slides back up eight seconds later.
Encounter
Only if the scale is insulted twice. Three calibration weights, and each one is only dangerous in its own lane.
| Count | Creature | XP each |
|---|---|---|
| 3 | Bronze Ox | 1,100 |
Base 3,300 XP; ×2 for three bodies = 6,600 adjusted, exactly the APL 9 Medium budget. This is the whole encounter — there is no second wave and nothing else in the room — which is why it is Medium and not Hard despite three CR 4 bodies.
The mis-weight clock. Every failed crossing attempt drops a bronze hammer on a plate: one loud, flat bang that everyone in the room feels through their boots. One bang: the oxen lift their heads. Two bangs: they come off the rail-stops and roll, and stay rolling until the beam balances or they are broken.
Round 1. Each ox runs its own rail end to end, at the same time, in the same direction. Nothing dodges out of the way for you and nothing changes lane. A creature in a lane when the run starts may dive clear with a Dexterity save DC 14, landing prone 10 ft to the side — which, on the middle rail, is the next lane over.
Tactics. The oxen do not pursue off the rails; they cannot. They reverse at the wall and run back. They ignore anyone standing between the lanes, ignore anyone on the apron, and stop the instant the pointer sits on the bull's head, wherever they happen to be. A party that works this out fights three creatures by standing still, which is the joke the room is telling.
Traps / Puzzles / Checks
What the beam wants. The floor opens the gate for 1,100 lb or more, carried on no more than two plates at any moment, moving one plate forward every six seconds. That is a bull: heavy, two feet down at a time, unhurried. Six people walking abreast weigh about right and are wrong in every other way.
| Element | Value |
|---|---|
| Read the beam | Investigation DC 12 from the doorway, or Perception DC 13 passive as they enter |
| Understand the cadence | Investigation DC 14 watching the pointer swing, or any History/Nature check on bull-driving — a character from farming country gets it free |
| Find the drover's pipe | Passive Perception 13; it hangs on a peg beside the door |
| Mis-weight | The hammer falls: one bang, and the clock above advances |
| Solved state | The pointer rests on the bull's head, the tongue drops, and the north gate is open for eight seconds — long enough for the whole party if they are already lined up |
Three ways through, all intended.
- Walk an ox across. The oxen are the calibration weights and each one is exactly right. Throw the rail switch (Investigation DC 13 to find it, Thieves' Tools DC 14 or Athletics DC 15 to throw it) and blow the drover's pipe: the ox steps off the rail onto the plates and walks the room corner to corner in a perfect two-beat. The gate opens as it passes the pointer. Cost: the ox is now loose in the room and no longer on a lane. It is not hostile. It is 1,100 lb of bronze that does exactly what the last note blown at it told it to do, and it will keep doing that.
- Load the sledge. Eleven blocks on the sledge is 1,100 lb. Dragging it in a two-beat cadence is Athletics DC 14, three rounds running, and two people on the rope give advantage. Each failure is a bang.
- Peg the beam. The mechanical fallback: Thieves' Tools DC 16 in the gallery (Athletics DC 13 to climb to it) drives a shim into the beam's pivot and holds the tongue down permanently. Cost: the gate never closes again, which is loud, permanent, and rings through the stone; and the scale never opens the trundle-gate at exit C, because the pegged beam cannot swing the other way.
Exits
None. The oxen carry nothing, the sledge blocks are dressed limestone, and the room's only valuable object is the balance beam, which weighs as much as a cart and is bolted to the wall. Say so plainly when someone asks — the room's reward is the exit and the trick, and a DM who hedges here has players prising up plates for ten minutes.
Scaling — APL 6 / 12 / 15
| APL | Adjustment |
|---|---|
| 6 | Two oxen, on the outer rails only — the middle lane is safe ground. All DCs −2, and the beam accepts any steady cadence rather than a two-beat |
| 9 | As written |
| 12 | Three oxen, and the mis-weight clock is one bang, not two. DCs +1. The gate stays open five seconds, not eight |
| 15 | Three oxen plus a Clockwork Sentinel on the gallery that throws the rail switch back every round, and the beam wants 1,600 lb. DCs +3, gate open four seconds — the party crosses in two groups or not at all |
- Pacing: twelve minutes if they think, four if they don't. The room is a thinking beat between fights and should feel like one. Behind schedule? Have the drover's pipe already in someone's hand as they walk in — a previous visitor dropped it on the apron — and let the ox-walk solution land in one exchange. Five minutes.
- Do not let the puzzle stall. If the table has been circling for eight minutes, an ox lifts its head, and the noise of it turning gives them the connection between weight and beast for free.
- If one player is solving everything, the plates are sprung: the person on the rope needs someone counting the beat out loud, and someone else on the switch. Split the job across three sheets and make them talk.
- Clue drip. Two objects here carry a clue well: the tally scratched into the beam's underside in a workman's hand, counting loads in and loads out (X19, the counterweights of the bull-gate work the same way), and the maker's mark stamped behind an ox's ear, which is the same mark on every Daedalan thing in the maze (X20).
- Callback. Daedalan Automata (W03) are predictable on purpose. A party that has already met a bronze thing on rails should recognise the shape of this: find the lane, leave the lane, and the monster becomes furniture. If this is their first W03 room, this is where you teach it.
Creature Cards
The oxen recur across the deck and their numbers live in the bestiary. The lanes, the cadence, and the bang are this room's and stay here.
Shared across rooms, so the full cards live in the bestiary: Bronze Ox. Every mention above opens the numbers here on this page.