Picture this: you are going about a typical day. Perhaps you are out with friends, enjoying a home-cooked meal prepared by your family, or spending time with your girlfriend. Upon waking up next, you are abruptly plunged into a bizarre, unfamiliar world, surrounded by five strangers on a boat that is rapidly sinking amid a storm. For Natsu Iwashimizu, this constitutes her new reality. Humanity has perished, and the only remnants of the Japanese population are five groups of men and women selected to be sent to the future, in the hope of preserving mankind's existence. While every other selected individual possesses a practical talent, such as martial arts, knowledge, or architecture, Natsu is a shy high school girl who cannot even raise her voice to shout. The new world is unimaginably dangerous, and although Natsu appears to lack useful skills, she must accompany the others as they make their way to the "Seven Fuji" in order to survive.