Yu-No / Yuno / Yu-No / Yuno

Yu-No / Yuno / Yu-No / Yuno - hentai released based on the visual novel "Kono Yo no Hate de Koi wo Utau Shoujo YU-NO" in 1995 at ELF.

Takuya Arima is a young and promising student. His father worked as a historian and conducted many various researches until one day he disappeared. Everyone said he died in another experiment, but Takuya never believed these rumors. During summer vacation, our main character receives a mysterious package from his father, which contains a strange device and vast information about the existence of parallel worlds and universes. At first Takuya takes it as a bad joke, but soon he realizes that this gadget can transport him to alternative worlds. Will he find out what really happened to his father?

This description corresponds to the original game, but in the series itself the beginning is too messy and it's quite problematic to figure out what's going on. There are of course differences, but it's better to stick to the original plot setup...