Having resolved the crisis in the Petrification Kingdom, Senkuu and his companions gear up to deal directly with the mastermind behind the petrification phenomenon—who supposedly resides on the moon. The ambitious spaceship project, however, requires immense manpower and critical resources scattered across the world. Thus, the Kingdom of Science exploration team kick-starts its transcontinental journey on the ship Perseus to gather them all. Equipped with modern technology and bolstered by the new, capable members in their ranks, the exploration team feels confident about setting sail to their first destination: America. They soon realize that the region now hosts adversaries controlling the resources they need, doing so with scientific technology which rivals and even exceeds their own. In a battle of science versus science, Senkuu and his team must outsmart their rivals if they are to have any chance of ensuring the continued survival and rejuvenation of humanity.

In a fantasy world where "jobs" are god-given from birth, heroes are born, not made—and Ein's job of "Appraiser" has put him about as far from the "hero" pedestal as possible. Used, abused, and eventually abandoned by his fellow adventurers, Ein decides it just isn't worth going on. Lucky for Ein, though, the end may just be the beginning, as well as a new lease on life. Turns out, his "worthless" job may just be the key to becoming a hero after all.

Since childhood, Kazuhiro Kitase has been able to dream of a different world. He can return to reality by falling asleep or dying, and he can pick up where he left off by sleeping again. For years, he has had many adventures alongside Mariabelle, a beautiful elf who works for the Sorcery Guild. On one of their escapades, they come across the lair of a dragon taking care of its eggs. They inadvertently wake the slumbering beast, who promptly reduces them to ashes. For Kazuhiro, it is merely a temporary setback, as he can simply go back. However, he is shocked to find Mariabelle herself safe and sound asleep next to him. Kazuhiro realizes that his dream world is an alternate reality altogether. In the meantime, he makes the most of this bizarre circumstance, introducing Mariabelle to the sights and wonders of Japan. Now, with their time together spanning two worlds, their real adventures have just begun!