A group of aliens arrives on Earth, and one of them becomes the King of Babylon, raising the Tower of Babel in the hope of returning to his home world. Technical failures cause his spaceship to explode, and the female lead is killed. The male lead and his troop remain on Earth, still looking for a way home. The heroine is reborn 2500 years in the past and meets him once more. Their reunion is fated to be short and followed by lasting loss, and a span of ten days becomes a gap they cannot cross. Through many lifetimes, the two hold on to the marks that let them know each other and wait for fate to bring them together again. The ONA runs 12 episodes and blends drama, fantasy and a tragic romance.