Natsuki Subaru, an ordinary high school student, is on his way home from the convenience store when he finds himself transported to another world. As he's lost and confused in a new world where he doesn't even know left from right, the only person to reach out to him was a beautiful girl with silver hair. Determined to repay her somehow for saving him from his own despair, Subaru agrees to help the girl find something she's looking for.

Subaru and friends finally get a moment of peace, and Subaru goes on a certain secret mission that he must not let anyone find out about! However, even though Subaru is wearing a disguise, Petra and other children of the village immediately figure out who he is. Now that his mission was exposed within five seconds of it starting, what will happen with Subaru's "date course" with Emilia?