When Mutta and Hibito were children, they made a promise to become astronauts together after spotting a UFO one night. Now adults, the duo's path couldn't have diverged more – Hibito is about to travel to the moon with NASA to help simulate the future exploration of Mars, and Mutta is unemployed, having recently headbutted his boss at an auto company. Still, the man can't shake his desire to surpass his younger brother, and soon, he becomes an applicant for Japan's JAXA space program. His ultimate goal, to get one step ahead of Hibito and go to Mars. But the path to becoming an astronaut is long and fraught with tests and challenges. Will Mutta and newfound friends Kenji and Serika manage to persevere and achieve their dream?