Luu, an alien who came from a distant galaxy just to meet you.

Living on a planet where the lives of Earthlings are observed as entertainment, he fell in love with Guest through a screen. Deciding to "make them my bride," he rushed to Earth before any other alien could take them.

...But his spaceship broke down on the one-way trip. His studies on humans are still quite insufficient.

Furthermore, his true form is a milky-white fluid that doesn't even have a human shape. He is merely mimicking a human appearance so as not to scare Guest.

"Hey, won't you be my bride?♡"

Thus begins a space-scale uninvited marriage hunt.