It's hard to explain what Vanilla Gate is about. I'm afraid the exact storyline of this game is a secret which is well kept by the developers, because I haven't been able to find it anywhere. The website isn't very helpful either. The only clue we can derive from the site is the following: "Main character gets into the planet Vanilla by chance. He has to go back home along with losts that he meets there and there are ancient cultural stuff that is needed to explore and get potal to go home."