Athletic, handsome, and tall, Kouichi Mizuki is regarded by his classmates as a man among men. As he prepares for college, he isn't quite sure what to do with his life, but his bonds with fellow basketball club members and classmates help him through this uncertain time.

One day, Kouichi vanishes from his bedroom in a sudden flash of light and finds himself in the center of a vast room, with gigantic men and women looming above him. Caius Lao Bistail, the prince of the titans, informs Kouichi that he has been summoned to become his bride.

For Kouichi, this situation is absurd; he just wants to return home to his friends and family. However, Caius is desperate and persuades Kouichi to give him one month before making a decision. Can love between two species of completely different sizes succeed? Exploding from just the tip, will Kouichi be able to fully accept Caius?