Dare Ichi Nin Kaeranai "Naraku" Ni Otosareta Ossan, Ukkari Ango Wo Kaidoku Shitara, Michi No Ibutsu No Tsukaite Ni Narimashita! Vol. 3 [Light Novel]

[Machine Translation] Kengo is a businessman who gets caught up in a heroic summoning and is banished to the "abyss" where he cannot return alive. He escapes by acquiring super-technological powers and begins a journey to unexplored regions with his friends. When Kengo and his friends set foot in the next destination, a mysterious large cave, they find themselves in a land of dwarves, a mysterious mole village, an underground hot spring, and other mysterious spaces. Amino, a young Dwarf girl, tells them of an ancient city rumored to be somewhere in the cave, and they set out for the deepest part of the cave - exploring the depths of the earth with the merry Dwarves to uncover the secrets of the great cavern!

勇者召喚に巻き込まれた挙句、生還不能の『奈落』に追放されたサラリーマンの健吾。彼は、そこで超技術の力を手に入れて脱出すると、仲間とともに秘境巡りの旅を始める。ケンゴー行が次なる目的地・謎の大洞窟に足を踏み入れると、そこにはドワーフの国や幻のモグラの里、地底温泉など不思議な空間が広がっていた。さらには、ドワーフの少女・アミノから、洞窟のどこかにあると噂される古代都市の話を聞かされた彼らは最深部を目指す―大洞窟の秘密を解き明かすため、愉快なドワーフ達と地底探検!!