At the end of the game last week, the party was stopped by a force that turned anything that crossed the final feet of the tunnel into a cloud of powder. Here’s the problem they face:
A mile-long steam tunnel leads down to the upper level of an open area that is well-lit. The last few feet of the tunnel feature a unique feature. An angled area of the tunnel looks much fresher, clear of any moss or dirt, and perhaps a little deeper than the rest of the tunnel. A pair of human boots lays at the edge of the area, with a skeletal tibia and fibula sticking out of each. The bones are cut off cleaning, as if with a hacksaw, just where the floor changes color. Looking around one finds other similar artifacts: a rat’s tails, bugs cut in half, etc. The angle of the area indicated that whatever was doing this was to the left, out of side around the corner of the corridor, and probably on the ceiling of the next space. The top of the tunnel is the same height as the ceiling of the next area.
The party begins experimenting by tossing sticks into the area, trying to throw them past the opening of the area beyond. Initially there was a scraping sound and then the thrown item disappeared in a puff of powder. When they continued their experiments, there was no scraping, but the items still disappeared. They put a hatchet into the area. The metal part of the hatchet was unaffected, but the handle disappeared, including the part inside the hatchet blade, which was fully surrounded by metal. A metal sheet was put into the area next, and was unaffected. They tossed a rock in, and it was unaffected. When they put a piece of wood behind a rock and shoved it in, the wood was disintegrated. After testing with various rocks, they found that a foot of stone would protect the wood. They hypothesized they might built up a pile of stones that would stop the unseen force. I ruled that piling up rocks would take a pretty long time. They have a mile long tunnel they would have to traverse, and the pile would not be just one foot thick at the base. I estimated it would take them about 16 wheelbarrows of rocks and 8 hours to do the job, and without a wheelbarrow or a ready pile of rocks, it would take about 4-8 times as long, which meant 3 to 6 days of work, working 12 hours each day.
An alternate plan of using the pyrotechnic fuse blasting caps they had found to tunnel through the concrete walls of the tunnel and go around the force. This had several problems. First, these caps are very small explosives, and they probably don’t have enough of them to do the job. If they returned to Mourne to purchase explosives, it still might not be a good idea to blow up sections of the material that keeps the hill from falling on them.
So, they have observed that non-organic objects seem unaffected by the unseen force, but organic objects, even sticks and rope, are utterly obliterated. As they continue to experiment, they notice that sometimes the item behind thick steel will be unaffected, at other times, it will be completely destroyed. The inorganic material does not reliably shield against the force. They hypothesize (Molecular Understanding) that the inorganic material does not so much stop the force as deflect it. For whatever reason, they don’t think it reliably protects them, which makes them worried about the tunnel walls themselves. They also suspect (Sense skill) that the rock they put in the danger zone as an original test is getting thinner, but they are not yet sure. The only mirror they have is a signal mirror, which has a hole in the center for directing the beam. Still, they put the mirror into the area, being careful to aim the reflective surface away from them. The stick supporting the mirror again disappears, but much slower this time. They can actually see the stick dwindle and then disappear, gnawed away by an invisible force.