On the night he turned 16, a drunk bunny girl barged into the home of Ren, who lives all by himself...! Calling herself Usara, she reveals that she is a Rabbit-Alien tasked with managing extraterrestrials on Earth. She informs him that he carries the blood of a certain alien race and because of that very fact, he is to be banished from Earth...! Despondent, Ren head off to say goodbye to his grandmother, his only remaining family only to be attacked at his destination by a dangerous, escaped Snake-Alien...!?