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Dungeon Exploration

What this is

Dungeon Exploration moves a party through a bounded site. Each action the party takes, each passing 10 minutes of time, and each risky move adds dice to the Danger Pool, which periodically results in a dungeon event. It requires a dungeon map and a known entry point.

Invoked by: the Basic Game Loop, when the expedition enters a dungeon; Clearing (when a hex's threats include a dungeon); DM judgment.
Invokes: Dungeon Encounters when exploration results in an encounter.
Returns to: the Basic Game Loop, or to Travel, when the expedition leaves the dungeon.
Bookkeeping: Activity Log (notable events, Danger Pool spills, time elapsed); character sheets (HP, exhaustion, items); dungeon turn tracker (forthcoming) for light, rests, and encounter cadence.

Setting up a dungeon expedition

When the party crosses into the dungeon, apply the steps below.

Step 1: Members and Marching Order

Record every member of the expedition: PCs, henchmen, summoned creatures, etc. Decide front, middle, and rear ranks.

Step 2: Provisions

Note provisions. Dungeon expeditions use the same provisioning rules as Travel.

Step 3: Light

Track every light source the expedition carries. Each die added to the Danger Pool (see below) reduces the remaining duration of every active light source by 1.

Source Duration Bright Dim
Torch 6 dice 20 ft 20 ft
Lantern (per flask of oil) 6 dice 30 ft 30 ft
Bullseye lantern 6 dice 60-ft cone 60-ft cone
Light spell 6 dice 20 ft 20 ft

If the expedition has no active light source, it is in darkness. Note: darkvision treats dim light as bright light and darkness as dim light, and cannot discern color.

Running a dungeon expedition

Once the DM begins to describe the first area of the dungeon, track real time and apply the rules below.

The Danger Pool

The Danger Pool is how time and risk are tracked while inside a dungeon. The Pool itself is a tray or cup that accumulates six-sided dice. The Pool starts with zero dice, and dice are added to it as the expedition spends time, takes dungeon actions, and risks attention in the dungeon. When the Pool reaches six dice (or more), it spills. The DM empties it and rolls all dice in the Pool. Any die that shows a 1 triggers a danger event. Roll 1d12 on the Danger Events table and add 1 for every 1 rolled past the first. After the Pool spills and is rolled, restart the Pool with zero dice.

Adding dice

Each die added to the Pool represents 10 minutes of in-game time. The triggers and the dice they add to the Pool are listed below.

Trigger Description Dice
Real Time Every 10 minutes of real time (including during encounters) +1
In-Game Waiting Every 10 minutes of in-game time spent waiting or resting +1
Risk An action draws the attention of the dungeon's denizens (loud noises, bright lights, etc.) +1
Dungeon Action The party takes a dungeon action. See entries below. varies
Move Dungeon Action: traverse to a connected area in the dungeon +1
Interact Dungeon Action: search, examine, listen, disarm, pick, or otherwise engage with the current area +1
Hunker Down Dungeon Action: find an out-of-the-way and defensible spot and wait. While there, in-game waiting dice slow to 1 per hour of in-game time rather than 1 per 10 minutes. Further dungeon action dice are not added. +1
Short Rest In-Game Waiting: 1 hour of rest +6 (+1 if hunkered)
Long Rest In-Game Waiting: 8 hours of rest +48 (+8 if hunkered)
Combat See note below. +1 / 10 minutes

Combat

Track real time spent on combat. After combat concludes, add 1 die to the Danger Pool for every 10 minutes elapsed. This will likely mean a difference between in-game time tracked with combat rounds (likely less than a minute) and real time (likely more than 10 minutes). The extra time covers checking and binding wounds, taking inventory, securing gear, and other such activities. Do not add dice from other triggers resulting from combat. At the end of combat, the party may take one Dungeon Action immediately (such as searching the fallen) without adding a die to the Danger Pool.

Spell durations

During combat, spell durations follow the spell description in rounds, minutes, or hours as written.

Outside combat, durations are spent per die added to the Danger Pool. A 10-minute spell expires after 1 die. A 1-hour spell expires after 6 dice.

In-game time elapsed

The party's elapsed in-game time equals the total number of dice ever added to the Danger Pool, multiplied by 10 minutes. That is, one roll of the Pool usually represents one hour of in-game time.

Danger Events

When the Danger Pool spills, the DM rolls 1d12 on the table below and adds 1 for every additional 1 rolled on the Pool past the first. A result of 12 or more is always a Combat encounter. The DM decides how the event will appear in play. The DM may choose an alternate event if the one rolled does not fit the situation.

The number of 1s rolled also scales the severity of the chosen event. A single 1 results in a minor event. Three or more could be deadly.

1d12 Event Description Examples
1 Provisions ruined Mundane supplies (rations, ammunition, torches) are damaged or lost Vermin or rot ruins several days' worth of rations or water; a quiver of arrows is broken or fouled; a magical container briefly malfunctions and ejects contents
2 Reputation damage If they make it out, the party will later find they have lost face Rumors have spread about something compromising (brutal kill, cowardly retreat, broken oath); a captive's testimony reaches outside the dungeon; a faction the party values downgrades them
3 Light disruption One or more active light sources are extinguished A gust of wind or water dousing snuffs all open flames; magical darkness fills the area; a lantern is dropped and breaks; an anti-magic effect ends all light spells
4 Spell disruption Magical interference threatens spells and slots a spell slot is drained (random level, random caster); the next spell cast in this area triggers a wild surge; an anti-magic field suppresses spells for 1 minute
5 Magic item disruption A magic item misbehaves or an ongoing magical effect ends A charged item loses 1d4 charges; a permanent item malfunctions for 1 hour; an attuned item temporarily de-attunes; an ongoing spell effect (mage armor, etc.) ends abruptly
6 Environmental hazard The environment harms the party Falling debris or cave-in; gas pocket (poison, sleep, fear); water surge; sudden heat or cold; spore cloud or magical disease
7 Cornered A passage or door physically blocks the known way out A door slams shut and locks behind them; a portcullis falls; a cave-in seals a corridor; a magical barrier forms
8 Time pressure The party faces a deadline A ritual will complete; a captive is about to be executed; a treasure is being moved away
9 Trap fires A trap or the next encountered trap activates without the possibility of detection A damage trap; a status trap (poison, paralysis, blindness); a security measure (alarm or lock)
10 Ally threatened The party's non-PC allies are pressured A henchman becomes frightened and leaves; a summoned creature is dismissed early; an animal companion panics
11 Detected The party is spotted or an alarm sounds A scout sees the party and flees to warn the rest; a magical alarm activates; tracks or a dropped item are found by patrolling denizens
12+ Combat encounter A patrol, group leader, or other hostile creature finds the party Invoke Dungeon Encounters; a common combat encounter for the dungeon; reinforcements join a fight