When they were young, the brothers Mutta and Hibito promised each other they would become astronauts. Now, in 2025, Hibito has followed his dream to become the first Japanese on the moon, but Mutta has just been fired from his job. His brother reminds him of their childhood promise, and Mutta decides once again to aim for space.
Recap episode. Mutta recalls how he first got accepted for the JAXA training program.
Recap episode. Hibito recalls the ordeal of his accident on the moon.
As Mutta and his teammates try to keep warm in the cold desert night, Mutta is reminded of recent events.
The astronaut candidates have reached the sixth, and final, day of survival training. But Mutta is down with a fever. Can Team E complete the training?
After completing survival training, the NASA astronaut candidates are tasked to participate in the upcoming Comeback Competition. Each team receives an advisory engineer, but Mutta's team is stuck with someone who won't help.
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.
During their car ride, Vince mentions that he considers astronomers his enemy, due to their supposed snobbery towards manned spaceflight. When asked who his viewpoint, Mutta responds that he considers himself to be his worse enemy, with Sharon being the one who helped him see that. As Pico joins them at the bar, Mutta's remark about earnest failures reminds Pico and Vince about their childhood friend, Rick, who used to make rockets together. Back when they were fifteen, they were under pressure to give up on their dreams and settle with becoming coal miners due to the town they were raised in, but they reaffirmed their dreams after seeing Brian riding the ISS.
Pico and Vince were pushed by their fathers and teachers to apply for their local technical college, which angered Rick, who felt betrayed by the others for giving up their dreams. Before they could make up with each other, Rick died in a car accident on the day Pico and Vince attended a career day for the mines. Distraught and angered by Rick's death, Pico and Vince reaffirmed their resolve to pursue careers as astronauts, as life is too short for unexciting things. Back in the present, Azuma and his group arrive at the moon base, where he reunites with Hibito, who thanks him for helping to save his life, whilst Mutta, Kenji and Nitta watch it on TV. As the day of the Comeback Competition arrives, Pico informs Mutta and Kenji that a rainfall the previous night could potentially cause huge problems with the sponge tires, the worst case scenario given them only an hour to do something about it.
With a limited amount of time before they launch, the team search for materials they can use to keep the sponge tires dry. Visiting the hotel's utility room, Mutta borrows some silicone sealant from the janitor, which he uses to waterproof the tires. With all their elements in place, along with Mutta's addition of a toy astronaut to represent the purpose of the experiment, the rover manages to make it 200m from the target goal before its battery dies, ranking them fifth overall and second amongst the AsCans. After the contest, they are approach by the winning team, whose director turns out to be none other than Naoto, who is working hard to develop a Japanese manned rocket.
As Hibito, along with Damian and Linda, begin their journey back to Earth, Mutta's group give Pico their rover as a memento of their time together. The day soon comes for the space module Orion to enter the atmosphere and a collective sigh of relief is heard as the parachutes are successfully deployed and the three astronauts land safely. Arriving in Houston, Hibito greets Mutta, giving him a piece of rock from the moon as a souvenir.
Whilst Hibito, Damian and Linda begin their rehabiliation, Amanti tells Mutta about a premonition she had about him, saying someone close to him will soon be stricken by a serious illness. Meanwhile, Sharon travels to a conference in America to propose the construction of a lunar telescope. Back in Houston, Mutta and the other AsCans are at Ellington Airport where they much learn how to pilot a T-38 jet as part of their astronaut training. Mutta is called up by Sharon who, after talking with Serika who is a big fan of hers, says she will be in Houston in two days, whilst Mutta starts to worry if she is the one Amanti mentioned.
The AsCans begin their flight studies, in which they must learn three weeks worth of flight knowledge in three days. Meanwhile, Sharon speaks with Daniel Morrison, a university lecturer from Hawaii, who expresses his interest in her telescope proposal and offers his support. She eventually arrives in Houston where she meets up with Hibito, who senses some limpness in her hands. After Sharon falls over whilst trying to carry some drinks, her assistant and Hibito check her into a medical center, where the doctor claims she is only feeling fatigue. Later that night, Hibito and Sharon head to a party Mutta and the others are holding. When Serika notices Sharon's battered cellphone, she is reminded of when her father was first diagnosed with his illness and discovers Sharon is showing the same symptons he had.
Mutta, Hibito and Serika accompany Sharon to a neurologist, where Serika fears she may be suffering from amyotrophic lateral sclerosis just like her father. As Sharon is admitted for more tests, Serika explains the details of ALS to Mutta, who is shocked to learn that it may one day kill her. As such, Mutta finds himself unable to concentrate on his written test and scores terribly. Following her examinations, in which she is properly diagnosed with ALS, Sharon is visited by Serika, who tells her about her father and motivates her to work hard on her research despite her illness. As Sharon heads back towards Japan, Mutta reaffirms his promise to help build her telescope. Later, Serika tells Mutta about a similar promise she made to get up to the ISS and develop a treatment for ALS.
After Mutta takes a make-up exam, this time managing to concentrate properly, he once again meets Deneil Young. With the top scoring AsCans being assigned to the best flight instructors for their T-38 training, Mutta, as the only one who had to take a make-up, is assigned to Deneil.
Deneil takes Mutta on his first T-38 flight where, unlike the other instructors, he flies at speeds of 6.5Gs. Mutta throws up on his first flight, though after hearing Hibito went through the same training, he decides to go on it again. He soon begins training to fly himself, tasked with relying on instruments instead of sight. Whilst intially having trouble, Mutta is soon encouraged by Deneil's advice and Sharon's hand written letter, encouraging him to train for what he can.
Hibito informs Mutta that he'll be returning to Japan for a week in order to be debriefed by JAXA and visit Sharon. Meanwhile, Mutta struggles with multitasking aspect of flying a T-38, not helped by Deniel's improvisations and a burger commercial that got stuck in his head. After giving him some advice on being a top pilot, Deneil later tells Mutta that he plans to retire once Mutta becomes an official astronaut. Meanwhile, Hibito and the other astronauts go drinking with Pico, telling him about his experiences with Deneil. As Mutta finally gets the hang of his training, Deneil tells him about how he salutes to pictures of pilots and would-be astronauts who died in flight accidents.
Mutta's flight training is progressing well. Meanwhile, Hibito heads back to Japan, where he is greeted by cheering g crowds and parades. He also gets a chance to visit Sharon.
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.
After completing training, Mutta is offered a spot on the backup crew for an upcoming ISS mission. This is a golden opportunity for Mutta to make it to space quickly. But he must consider what he truly wants to do.
Mutta and Hibito are selected for a magazine cover. Mutta is excited, but he notices that Hibito is acting strangely.
Hibito struggles with the panic disorder that's afflicted him since his ordeal on the moon. However, he requests that his condition be kept secret from Mutta, who may have found a way to improve the lunar rover.
Mutta comes up with an idea to prevent vehicular accidents on the moon. Will NASA accept his proposal?
Mutta's proposal to improve the lunar rover is received well. But he still hasn't convinced Chief Butler to let him train for lunar missions. Desperate for ideas, Mutta researches Chief Butler's history for clues.
Mutta's proposal to add a windshield to the lunar rover is received well. However, Chief Butler is still reluctant to allow Mutta to train for lunar missions. Mutta decides he must try something more dramatic.
Mutta has convinced Chief Butler to allow him to start training for lunar missions. Meanwhile, Hibito is in Russia, trying to overcome his panic disorder.
Hibito continues to struggle in rehab. Russian astronaut Ivan Tolstoy shows Hibito videos of his daughter as a child, learning ballet. Will the videos give Hibito his answer?
Inspired by Olga's performance, Hibito continues his rehabilitation. Ivan comes up with a unique approach that may start Hibito down the path to recovery.
NASA and JAXA have decided to bring Hibito back to Houston, placing him in a supporting role. Hibito has no choice but to pack up and make his farewells.
Hibito has returned to Houston from Russia. At the same time, Mutta begins his journey to the moon with NEEMO training.
Mutta's idea for improving the lunar rover has earned him the right to participate in NEEMO training. He has taken one step toward the moon.
Mutta is now underwater participating in NEEMO training. He's happy to be assigned to the same team as Kenji, but it turns out that he shouldn't be celebrating.
Only one of each team's two Ants will be chosen to go to the moon. Since the beginning of his journey, Mutta has worked with Kenji, so he isn't sure what to do.
Mutta and Kenji are forced to compete for the chance to go to the moon. Initially unsure as to what to do, Mutta benefits from Andy's advice, which helps him settle down and devise a new plan.
Mutta and Kenji have overcome their initial shock after hearing that only one of them will be chosen to go to the moon. Now that they're working together again, everything seems to be going right with their construction of the Moonbase.
Mutta has completed NEEMO training. His final idea impressed many people in NASA. Meanwhile, back in Houston, Hibito continues his rehabilitation.
Mutta has completed his NEEMO training and now waits to learn if he will be heading to the moon. Back in Houston, Hibito also completes his rehabilitation training. All that remains is to demonstrate to NASA that he has made a full recovery.
Hibito is worried about the upcoming test that will decide if he will be allowed to return to space. Uncertain, he turns to an unexpected person for advice.
Mutta has been chosen to go to the moon. First, he will serve as Vince's backup. Now, Kenji and Nitta must learn what the future has in store for them.
Hibito begins the test that will determine if he can return to active duty. However, Chief Butler has planned a surprise for Hibito.
Hibito takes the test to determine if he will be allowed to return to active duty. While Chief Butler issues a green card for a false malfunction, to see how Hibito reacts under pressure, another malfunction also occurs that Butler doesn't expect.
Hibito has passed his test to return to active duty. With that over, Mutta can focus on starting his backup crew training for a lunar mission.
As Sharon makes a new proposal to NASA for the lunar telescope, Mutta continues his training in the desert. However, Chief Butler is still seeking a backup captain for the mission.
Mutta has been assigned to the CES-62 backup crew, but his fellow members aren't keen to work together. Will the arrival of Eddie Jay, their leader, turn things around?
Eddie Jay's arrival has given the CES-62 sub crew a much-needed jolt. After a night jog brings the crew closer together, Eddie suggests that the crew members share their stories.
Mutta has returned from his training in the desert and gets some rest as Christmas approaches. Meanwhile, Kenji and Nitta finally learn about the mission they've been assigned to.
It's New Year's, and the Nanba family is together in Houston to celebrate. Mutta feels good, as he trains for the moon and talks to Serika, but Hibito doesn't seem to be in a celebratory mood.
Troubled by Hibito's disappearance, Mutta's performance begins slipping. However, a conversation with Chief Butler reassures him.
Hibito's disappearance is distracting Mutta during training and he makes a critical mistake. What will Hibito do next, and will Mutta be able to get his act together before the actual launch?
