The year 2006. Two brothers, Nanba Mutta (age 12) and Hibito (age 9), happen to spot a UFO headed for the moon. The experience inspires them to make a certain promise.

After advancing to the second exam, Mutta realizes that the other applicants are much better prepared than he is. Desperate to prove himself, he stakes everything on the lung capacity test, as he has confidence in his trumpet-trained lungs. However, as the other applicants drop out, he finds himself in a heated battle with Itou Serika. Who will come out on top?

After completing the second JAXA exam, Hibito invites Mutta for a free trip to Houston, Texas, through NASA's family support program. Upon arrival, he finds himself chased by a pug named Apo, and is then reunited with Hibito. However, Hibito expresses disappointment.

After learning that his former boss has told JAXA about the headbutt incident, Mutta has given up hope on passing the exam. To cope, Mutta falls back on his childhood habit of multitasking like crazy when something bad happens.

When the robber known as the fire extinguisher man strikes the restaurant where Mutta is, he's in trouble. But once the dust settles, Mutta has become a national hero for capturing the criminal. However, it appears there's more to the story.

After five days in their sealed boxes, each team is exhibiting a pronounced personality. Mutta's Team A is rowdy, while Team C is quiet. However, Kenji's Team B appears to be a little gloomy.

The exam in the sealed box is halfway over. Mutta's Team A suffered an accident when Fukuda's glasses were broken. But Furuya, the one who broke them, requested a new pair. Meanwhile, Team B must deal with an alarm going off in the middle of the night.

It's their final day in the sealed box. Mutta has enjoyed his two weeks with the team, and he wishes to avert ruining their bond, as they make their final decision.

The third astronaut selection exam has finally ended. Team A used rock-paper-scissors to select two members. Whose dreams are still alive?

With four days before the launch, Mutta and his family arrive at Kennedy Space Center for one last meal with Hibito before he heads into space. Mutta uses this opportunity to hand Hibito a very special DVD-R.

It's finally the day of the launch, but the weather doesn't look good. On top of that, Apo's run off, so Mutta has to go find him. While searching for Apo, Mutta comes across a suspicious old man.

Hibito and the CES-51 crew have landed on the moon. Meanwhile, Mutta has returned to Japan to await his final exam results. He's especially concerned about using up his luck before the results are announced.

Two hours have passed since JAXA was supposed to notify the candidates, and Mutta hasn't received a call. When the phone finally rings, he's told to go to a nearby park. What will his fate be?

Hibito is able to save Damian, but he's running out of oxygen. Freddy and Buddy are trying to catch him, but they won't arrive before his oxygen depletes. Is this the end?

As Azuma makes his way towards the moon, Mutta's team works on testing the rover, learning of what flaws they need to fix. The team consider following another team's example and going with a glider instead of a ground rover, but Pico points out that the wind would cause issues with that plan. Using his engineer insight on how to overcome their obstacles, Mutta suggests that they make the rover's tires out of sponge, so they can have larger tires that still fit inside the rocket whilst also reducing costs and providing shock absorption. Impressed by this idea, Pico decides to give the team advice on their parachute, encouraging them to think of the rover as a spaceship containing their comrades. With Mutta's ideas and Pico's advice, the team manage to put together a working rover complete with a functioning parachute. Later, as Mutta is invited by Pico for a drink, Vince takes him for a drive.

After Mutta completes flight training, he officially becomes an astronaut. Now he must wait to see if he will be assigned to a lunar mission.