The Sunken Towers

Deep in the wilderness are three towers, slowly sinking into the bog. Once, this was the site of a great battle, for the dark waters are full with mummified soldiers of a bygone age and their treasure gleams below the surface like hidden suns. Three witches live here - sisters in souls, one in each tower - feeding on children lured into the bog. Such gruesome deed can only be countered by another, and now you have come here to end them.

This is a fairly intricate encounter that relies on the exact positioning of terrain features in setup. The characters start on dry land in low-right corner and they have to wade through the marsh to kill the witches. The water quickly becomes deeper: one square away from dry land, it reaches the characters to the waist, two squares away it reaches to the neck, three squares away the character must roll STR to swim or sink. If they proceed with caution, poke with a stick or similar, they can measure the depth of an adjacent square without stepping on it.

Because it is always waist-deep one square away and neck-deep two squares away from dry land, you don't have to consult the map once setup is done. You just have to count distance to closest land. in this sense, everything is out in the open - only the logic is not. The players will figure it out themselves, eventually, and once they do they will be able to anticipate which water squares are safe and which are not. To enable this, it is important that the characters move one step at a time, at least in the beginning, and that you emphasize the gradient: land - waist - neck - too deep.

Once not on dry land, movement is halved. You should be open with this, because it established from the start that it is important exactly which square a PC enters. The added split-second needed to calculate (1, 2, 3-4...) should also provide you with a small window to describe how the water becomes deeper, shallower, or remains the same depth.

The treasures should be marked on the board from the beginning: they are lures to draw characters into the water.

The bog-men should appear at randomly determined location. There are 20 islands (not counting the starting corner) so you can roll a d20 if you want.

The sunken towers

Target = 10+armour (or: target 10, subtract armour from rolls)
x= deep; roll str to swim or 1d4 fatigue
■ = submerged door
□ = door above surface
/// =  land, actions are EASY. 1 square away water to waist/movement is halved, 2 squares away water to neck/movement is halved, actions are HARD
ø = treasure
o = Bog witch, 3hp, fights as 3HD, Life drain (1d8 magic damage + save or dying, if attack deals at least 1 point of damage, the other witches gain 1 hp - resurrecting them if dead)

12 bogmen live in the murky waters, 1d4 appear each time a character steps into the water. 3HD, chain+helm (6 armour), Cursed curveblade (1d10, magic damage, breaks on a 1)

Timer: each 1d4 rounds, all PCs not on dry land must save/STR or are pulled 1 square towards deeper water. Characters already in deep water suffer 1d4 damage (no save) and must roll again to swim .

Treasures:

1. 1d6 gold
2. Mirror shield: +3 defense against magic attacks only.
3. Bronze curveblade (see above)
4. Bog head
5. Ambushed by bogman
6. Bronze helm: 1 armour, +2 against magic. Breaks after 1 day unless kept wet.

1d6 towers

I've always preferred longer entries in encounter tables, like hex descriptions. An excellent format is "X, but Y" or a description with a twist, because it focuses on how this encounter is different from your first guess.

A very good example of this is the situation-type encounters of Hidden Kingdom. They outline a situation - like a damsel riding her Palfrey at great speed - and then presents a d6 table of further details if the players interact with her. Only then is it determined if she is enjoying the lands that belong to her, a bandit who has teamed up with a Black Knight, an elf, fleeing from a cruel Powerlord or rushing to aid a lover in distress. I like this a lot because it fills the situation with potential: for a second, the Damsel is all those things. And in fact, you could easily decide that all options are true if you want a richer encounter, instead letting the PCs decide which facet of her personality they want to act on. Punish her for her misdeeds with the Black Knight? Reasonable, but maybe the pursuing Powerlord is a more pressing concern? Or maybe Love is the highest virtue, and all trespasses can be justified if she reaches her lover in time to save his life?

Here are 1d6 towers.

TOWERS
You spot a small tower in the distance. Clinging to a rock it rises over the surrounding foliage like the head of a drowning man, easy to lose sight of forever. Overgrown with vines and in bad repair the tower seems deserted at first, but a sudden shadow or instinct gives you doubt

If the tower is approached, roll 1d6:

1. Only the sturdy walls remain of the tower; into this stone cylinder a spindly troll has climbed, making itself a home. The troll hides from sight and hurls child-sized rocks fallen from the structure to protect its nest. The projectiles deals 3d6 damage on impact and continues skidding and bouncing for another 1d6", dealing half damage to those in its path. Armor has no effect.

The troll has a golden ring in its nest.

2. Built by monks to house them in times of strife, the tower has a plethora of narrow windows and a door that only the tallest ladder can reach. Anticipating their doom the monks burned their sacred texts and drank poison to protect their sacred knowledge, but due to cowardice, fate or divine will one of their lot survived. Ancient and bewildered, he now spends his time recreating the scrolls from faltering memory or contemplating the vial of poison that failed to kill him.

In the library are two scrolls that functions as cleric's spells, but if stained or ever touching the ground, they burst into flame in 1d4 rounds.

3. In the tower lives a band of robbers under the command of Radferd of Suddane. They have few treasures and only a little food, but are well equipped and motivated fighters.

4. A flock of harpies stay in this tower. Dread black against the pale twigs and bones that make up their nests, the harpies come here during spring to collect child-slaves to mine their native mountains. Haughty and prone to opportunistic cruelty, they are formidable fighters but reluctant to fight since any damage can lose them their place in the hierarchy of the flock. If nothing can be gained from combat, they curse or coo at interlopers, drop rocks and feces from above, or circle tirelessly around them to spoil their sleep and alert predators and miscreants to their presence.

2d4-2 children are kept in the tower, hungry and maltreated but eerily well-kempt and clean.

5. Locked inside the tower is a wounded knight. Delirious with fever and weak from loss of blood, he was trapped here by two outlaws who hope to secure a ransom for his life. The outlaws will return in 1d6 days, but the smell of blood will attract local monsters within 1d4 days unless the knight's wounds are treated.

6. A band of goblins led by Gultooth Tuck have made this dank tower their home. The hill and surrounding forest is littered with traps, and while many of them are poorly made their rusty teeth and grime-covered spikes make a powerful deterrent for would-be attackers while also providing the outpost with the occasional animal. The goblins are armed javelins and bows, the arrows of which they demonstratively spit on to further dissuade intruders.

The goblins have been fairly successful in their raids, and among their loot is a enchanted sword.