One day, highschool student and part-timer Yomogi Asanaka is on his way home and meets a starving man named Gauma, a self-proclaimed "Kaiju user". After generously giving him a leftover sandwich Gauma swears he would repay him one day and ends up following him around. One day a girl named Yume Minami infamous for asking boys out but...

Yuta Hibiki has a case of amnesia who finds himself waking up in the home of Rikka Takarada, one of his classmates. Other than that, he had no memory of who he was at all. Fortunately his friend and Rikka are both kind enough to stay by his side while he worked on regaining his memories. However, Yuta was seeing things that his friends...