A world where civilization has collapsed due to the invasion of mechanical lifeforms, leaving only deserts and ghost towns. To fulfill his dream of saving the few remaining animals, the boy Noah has mechanized his body, surviving alone in the harsh environment while building an ark. Then, the Celestial Keseed, who seeks the ark, appears from another world. Though he tries to get close to Noah and find an opportunity to seize the ark, his encounters with Noah's sincerity and kindness leave him torn between his mission and their growing friendship. What is the true nature of the mechanical lifeforms? What will Keseed decide? And will Noah's dream come true?