The slight tremor that I had felt last night had already completely left my mind. After waking up at 9 a.m., I started the washing machine and ate a simple breakfast while waiting. When I went outside afterwards to hang out the freshly washed load, I noticed a square hole in a corner of my yard that looked roughly one meter long on each side. I tilted my head in puzzlement. Wondering what it was, I lit it up with a flashlight and discovered a flight of stone steps that led underground.
“An underground room? I don’t remember hearing about this when I bought the house.”
My wristwatch indicated that it was 9:55 a.m. Both today and tomorrow were days off on my schedule, which meant I had nothing planned. With a flashlight and an oil lighter in hand, I gingerly descended the stairs. Judging by the direction, it led underneath the neighboring plot. As much as possible, I wanted to avoid trouble with my neighbors. While considering whether I should seal this hole with two-by-fours, I carefully continued down. The lighter in my hand remained lit, from which I gathered that I didn’t have to worry about oxygen.
“...This is really deep. How far does it go?”
By feel, I determined that I had descended roughly the height of a ten-story apartment building by the time I finally reached the bottom. I heaved a small sigh of relief at the sensation of my feet on flat ground again, then turned around to look at the flight of stairs that I’d just come down. It was a lot steeper than I’d thought. Just thinking about having to climb all the way back up to get out was enough to make me feel down.
“This underground area is pretty spacious. If I put in a bit of time and effort, I might be able to use it for something.”
Pointing my flashlight in all four directions and up and down, I gauged the space to be about fifteen meters on each of the four sides with a clearance of more than three meters. The floor was paved with stone but with absolutely no gaps whatsoever between the paving. As I continued looking around, I noticed the wall in front of me reflecting the light of my flashlight.
“A...door?”
There before my eyes were sturdy-looking double doors with a metallic sheen that towered more than two meters high. I hadn’t noticed it earlier due to its black coating.
“A bomb shelter? Or an abandoned military facility from WWII?”
There were no weld marks between the metallic doorknob and the door, almost as if it was all one, single piece. Thinking that it would probably be a good idea to check out the inside first before reporting this to my local government office, I grabbed the doorknob. That instant, a voice suddenly rang out.
<First Contacter confirmed. In accordance with World Order, hereby activating the Dungeon System. ETA to the activation of all dungeons: one revolution.>
“Wh-What?! Where did that voice come from?!”
The cold, robotic voice was surprisingly loud, causing me to clasp my hands over my ears. However, that did nothing to decrease its volume. It was almost as if the voice was speaking directly inside my head.
<As the reward, you are hereby granted the Character Card “Akane the Glamorous Kunoichi,” the lifting of your card possession limit, expansion of your skill slots, and the authority to choose your skills. Native ability “Card Gacha” has been installed.>
“Huh? Kunoichi as in a female ninja? Card? What card?”
<Dungeon Roulette has been spun. Fixed coordinates confirmed. Dungeon name: Abyss. Difficulty: A. Drop rewards: A. Available Enhancement Element: A. Congratulations. We look forward to your progress towards a new transformation.>
The strange voice cut off as suddenly as it had started. Before my eyes was a single, glowing card floating in midair.
“What...is this?”
The mysterious underground room that had appeared all of a sudden, the strange doors, and the voice that had almost given me a headache and its incomprehensible message had left me so bewildered that I did not have the mental capacity to worry about the impossibility of something floating in midair by itself. As the card was glowing on its own, I didn’t even have to direct my flashlight at it.
Before reaching out for it, I carefully studied the card. On its surface was such a realistic depiction of a person that it almost looked like a photograph. A black-haired woman in what appeared to be a ninja outfit was posing with a kunai — that’s what those small ninja daggers are called, right? — in hand. My general impression was that this looked like a card from a card game.
Slowly, I reached forward and grasped the card. It felt rather strange to the touch. Despite being as hard as a plate of metal, the surface felt matte. I flipped it over and found words written on the back. It was in Japanese.