What lies at the bottom?

Gavin was a typical miner from the abyss, farming materials hoping to get rich with a lucky find. But as a tragic accident occurred, Gavin was pushed of a suspension bri that was stretched over the abyss. He fell into unknown and was just mentioned as one under many accidents but as he opened his eyes on the bottom of the pitch black hole, he was met with a strange window. (World building is the same as in Made in Abyss) (Cover is not mine. Contact me if the author wants it taking down)