mel-mel's manga / #action(17)

about a man, every time he sleeps he dream of another world and in order to get out and survive he must defeat the enemy or the master of the dungeon they are transported in. He experience many hardships and along the way he also met another person with similar situation as his. He saved that person only to know that in real life that person is a kid of a billionare so they begun to train and prepare for the next challenge this time they packed well because there is no certainty on what time or how many months will they be returned to their original world. only read until chapter 57