Meifu No O No Kamigakushi (Chara Bunko)

[Machine Translation] While excavating an ancient burial mound, he encounters a falling rock! What's more, he wakes up in the underworld! The archaeologist Izuki, who was on the verge of death, was saved by the King of the Underworld, Rui. He said, "I will only allow you to stay here for a month while you heal from your injuries. Although he is arrogant and cold, he rushes to Izuki's aid when she is in danger and protects her from evil spirits. In fact, Izuki has a history of having been hidden by the gods for three months ten years ago. He begins to suspect that he might have been here before!

古墳の発掘調査中、落盤事故に遭遇!!しかも目覚めた先は、なんと冥府―!?瀕死だった考古学者の伊月を助けたのは、冥府の王ルイだ。「怪我が治る一か月間だけ滞在を許可する。ただし俺には一切関わるな」尊大で冷たいのに、伊月の危機には駆けつけて悪霊から守ってくれるルイ。実は伊月には、十年前にも三か月間の神隠しにあった過去がある。もしや以前にもここへ来たのではと疑い始めて!?