King of the Hill Armies: Two, no Special Characters, Vehicules (including Dreadnaughts) or Major Daemons.
Campaign Players:

• Imperial Guard (JP)
• Chaos Cult (Ti-Blanc)

Setting
Your forces return from a victorious raid on an enemy outpost on the volcanic planet of Kakuna. You are about to pull back and board your pick-up when the intercom crackles.
"Battle force, this is your pick-up ship. We cannot send for you as the whole area you are in suffers from intense seismic activity. Move to Mount Rapvisk, 10 kliks from your current location. See you there"
Upon hearing that your forces have forced marched to Mt. Rapvisk. However when you arrived to take the position, the enemy has managed to muster a small force to prevent you from leaving. You must bring some of the plunder you have gained back to base in order to have it analysed as this could give you much important data on the enemy.
Just fighting off the enemy would be enough, but a nearby mountain has gone ballistic and is spitting lava. You will barely have time to move your troops to the transport.

Battlefield
Setup a standard wilderness scenery with a few large structures, use mostly hills and trees.

Orders

Raiding Army You are to enter you troops inside the transport. The dangerous field conditions make it so you won't have much time to engage and destroy.
Defending Army You know the raider' Commander must have a good idea as to the important information he has. You must quickly move and destroy every enemy characters.

Game Duration
The game lasts until either one army is totally destroyed -OR- the molten lava cut off the way of the attacking army. At that point all troops on the hill will be considered to have succeeded in escaping while the others will be considered destroyed and the defender will add the victory points according to the troops on the table. Troops on the mountain are considered to have escaped.
When we played, after 3 turns the whole mountain was cut off, so we opted to keep going until the annihilation of one army.

Special Conditions
AFTER both players have setup, one player rolls a D6. on 1-3 it is the left edge, on 4-6 the right edge. From that side comes a flow of lava. BEFORE the first turn, the lava has reached 2D6 inches. Remove all non-hills terrain it touches.
The lava moves D6 inches AT THE START EVERY MOVEMENT PHASE, before charge declarations. If a 6 is rolled, then a D4 is added.
The only safe place are the pickup point and staying away. Models on a terrain element that is destroyed by lava are automatically destroyed. A model on a hill surrounded by lava take a Str 3 hit, increasing by one every turn (4-5-6-...) until it is dead. Note that hills that not fully surrounded by lava do NOT suffer any wounds. Models on the mountain DO suffer these wounds.
Characters immune to fire (such as the Eldar Avatar) will not suffer any wounds from the lava, but every time the lava advances they will have to test under their strength on 2D6 or be displaced by the same number of inches as the lava.

Campaign Outcome
Since I was eerily lucky with my lava movement it moved 8-10-5, which destroyed my command squad and half my ratlings. Before I played my 3rd turn, the game was over ! So we both decided to let the game going.
So in the end, my displacer field saved my life though my Commissar passed REAL CLOSE to the lava. In the end, the Demagogue and Commissar Yannick (the famous guy's cousin) fought on top of the hill and the Commissar walked away hurt but alive.
As a campaign choice, we decided that his transport would nevertheless come and capture the Commissar. The next phase of the battle would be with the Empire trying to free the Commissar from the Chaos forces.