Kamen rider build x Honkai Star Rails: The Genius rider of the Astral Express

In the vast universe where humans follow the path of beings called Aeon, the Aeon are different from other things. The enemy of humanity is Anti-matter Legion who attack humanity and Stellaron who born to manipulate humans.

However, a young man with genius intelligence on pair with the space station's scientist, and the young man with his missing past and want to know who he is or why is he here on the space station and wonder why did he have a driver?

But the most powerful box known as Pandora Box, a mysterious box hold by someone else, and now it create Fullbottle for someone to use it. Now it's up to the young man protect the universe with the power of science and love and peace.