A beautiful girl, Lily, and her butler, Sebastian, suddenly appear at illustrator Shiro Suda's doorstep. To an upset Shiro, Lily said, "From today, I will be your wife for a limited period of time! And I'm going to ask you to help me make a baby! And you will help me to make a baby!" Marriage? Making a baby? And with an alien! What will happen to their forced life together...?