Chapter 1 [The Cave, 1. Departure]
First, it's preparation. I'm not foolish enough to charge into an unknown place without any preparations. Whether the other side of the door is a different world or just another place in this world is unclear, but it seems like a cave, so lighting is essential. While I didn't sense any strange smells or suffocation when I opened it earlier, there's a risk of suffocation if carbon dioxide has accumulated. In addition to a flashlight, candles or torches would be necessary. If the fire goes out, it means there's no oxygen. If explosive gases have accumulated... well, in that case, you should be able to tell by the smell. But I heard propane gas is odorless... Anyway, just being nervous won't progress the story. After opening the door, throw a lit match inside and quickly take cover. If it doesn't explode, you can enter.
Let's return to thinking about lighting. I remember there was a lamp. My dad said it was a souvenir. It was like a toy, but it should have worked if you filled it with lamp oil. As for weapons... a box cutter or fruit knife won't cut it.
Oh, well. I'll go to the home center and look for something. However, if I blatantly buy something that looks like a weapon, the public eye might become troublesome. I'll try to find something that doesn't look too menacing but can still serve as a weapon.
I threw a lit piece of paper inside, but there was no explosion. After confirming that it didn't burn unusually strong or extinguish too quickly, I checked the exploration equipment.
"Headlight, spare flashlight, lamp with lamp oil, canteen with portable food, first aid disinfectant and band-aids, work gloves, weapons include a multi-tool knife, shovel, and nail puller, and a golf ball as a makeshift shuriken. Also, a digital camera for recording, and I've tied the balcony railing with a rope for a lifeline, and..."
I don't plan to stay long, so this should be enough. I'll just quickly look around the nearby area and return in a hurry if something happens.
When I stepped into the cave, I felt a momentary dizziness, probably due to tension. It seemed like I was enveloped in a dazzling light, but it must be my imagination. After stopping for a while to confirm that nothing was wrong, I began to walk slowly deeper.
The flame of the oil lamp remained unchanged from when I was indoors. The light hasn't weakened, so there seems to be no worry about lack of oxygen, and the fire hasn't unnaturally intensified, so there shouldn't be an excess of oxygen either. Oxygen can be harmful if too little or too much.
No strange smells, no sounds. The sensation of the ground is firm. It doesn't seem to be quicksand, but I'll proceed cautiously. Whether something happens or not, I'll return to the room when the lamp oil is less than half. Exploration can be done little by little. Also, it would be great if I could bring back something that seems like evidence.
The cave is a single path with no branches or even cracks. Despite some bends, it seems to generally stretch straight.
From the feeling of poking it a bit, the walls seem hard. It wouldn't be easy to shave off any fragments. Although there are wrinkles or irregularities in some places, the surface is smooth with no cracks. What looks like a crack in the wall is actually a smooth depression, not a crevice. There are no signs of processing, but both the walls and the ground are strangely smooth. It's odd that not even a single pebble has fallen, and there are no footprints. There are no traces of human intervention, but there's a somewhat unnatural feeling. It's reminiscent of a movie set. There's no moisture.
As I looked around for any signs of living beings, I found one.
A transparent gelatinous mass with a diameter of five to ten centimeters. It feels like a hemisphere resembling the slimes in games. When I gently poke it, it quivers weakly as if trying to escape.
No... could this be a real slime?