Plot

A man is left in space due to an unfortunate accident while another man on Earth struggles to bring him back safely.

Set in 2030, when the manned lunar exploration project has progressed considerably. Astronaut Hwang Seon-woo, was stranded on the moon alone in space beyond 384,000 km due to an accident, while Kim Jae-guk, the former head of the space center desperately trying to save him. On the other hand, Moon Young, general director of the National Aeronautics and Space Administration space station, has a hidden secret.

In the near future, South Korea's first crewed mission to the moon ends in a tragic disaster when an explosion occurs on board. Five years later, a second human spaceflight is launched.

Woori-Ho was the second attempt by Korea to launch a moon exploration rocket and become the second country after the United States of America to carry out research on the surface of the moon for energy sources such as Helium-3. Lee Sang-Won (Kim Rae-Won), Cho Yoon-Jong (Lee Yi-Kyung), and Hwang Sun-Woo (Doh Kyung-Soo) were selected to be astronauts for this crucial mission because of their expertise in the area. Though Hwang Sun-Woo didn't have a lot of experience as a pilot, due to his Navy Seal training, he got an edge over the others because he had the experience of being in extremely difficult situations. Hwang Sun-Woo's father, Hwang Gyu-Tae (Lee Sung-Min), was the tech lead in the first mission that happened five years ago. The spacecraft had exploded back then as soon as it was launched. Gyu-Tae was no longer alive, but his son, Sun-Woo, wanted to honor his memory and make this mission a success.

As soon as Woori-Ho was launched, another anomaly happened. Due to unprecedented solar winds, the satellites had to be shut down, and even the USA's manned lunar gateway was affected by the crisis. The three astronauts were out there in the void approaching Lunar orbit, and the Korean team had no means to communicate with them. They all took a breath of relief when somehow, the astronauts made contact and told them that they were all safe.

Lee and Cho were checking the spacecraft from the outside, and they believed that they would be able to repair it. Sun-Woo, who had limited knowledge about the technology, was getting all paranoid at every little alarm inside the spacecraft. The astronauts noticed that there was a leak in the fuel tank, and before they could even process this information, there was a huge explosion in which Cho Yoon-Jong immediately lost his life, though Commander Lee managed to hold on to his hatchet and not get blown away by the explosion. Lee had realized that he wouldn't be able to make it out of there alive, and in his last moments, he asks Sun-Woo to reboot the full system power so that he was able to get the communications on and return safely. Sun-Woo stood there and saw Commander Lee open his hatch (His space suit was anyways leaking, and he had no hope to survive) and disappear into oblivion forever. Lee had said that his dead body attached to the ship would affect its movements and safe landings.

Back at the space research center, a decision was made to call the only surviving scientist who had designed the spacecraft. Only this person could guide them on how to remote access the command module and bring the spacecraft back home. That's when Kim Jae-Guk (Sol Kyung-Gu) was contacted, and immediately brought to the space research center. Kim says that the Command Module can survive for 3 weeks in its existing state and asks the authorities to ask for help from NASA who have the lunar gateway orbiting the moon. But NASA and the International Space Committee (ISC) had expelled Korean for trying to pursue their own technology outside the consortium. The Minister (Jo Han-Chul) requests Kim to save one life. He is told that the life in question is the son of Kim's colleague Hwang Kyu-Tae, who worked with him on the first space ship the Narae-Ho and committed suicide upon mission failure.

Kim re-orients the spacecraft using the Thrusters to face the sun and saves Sun-Woo from freezing to death as the heating system was damaged. Kim then works on bringing the spacecraft back home. The spacecraft also enters a stable moon orbit with Kim's maneuver.

But Sun-Woo was of the opinion that instead of waiting there and putting his faith in others, he should try to land on the moon. He was adamant about making use of the autopilot and whatever help and guidance he could get from the space center. Kim tells Sun-Woo to wait for the lunar gateway which will arrive at his position in 2 days. Sun-Woo tells Kim that he was not able to save his father, and he could fail again. Sun-Woo was ready to defy the odds and became the first Korean to carry out explorations on the surface of the moon. Sun-Woo achieved the impossible and made his entire nation proud when he lands the Lunar Module on the surface of the moon. But still, the battle was only half won, and the danger of a meteor shower was looming over his head.

The dreaded meteor shower started happening when Sun-Woo was collecting samples from the surface of the moon. He had to rush towards his aircraft, and when he tried to propel his lunar car forward to escape that region, he met with a terrible accident as meteors impacted near him. With great difficulty, Sun-Woo reaches and enters the lunar lander module. He manages to launch it before the meteors hit the lunar module site and gets into the command module orbit.

The docking with the command module is completed, but before Sun-Woo and transfer into the command module, the meteor shower hits the command module and completely destroys it. On Kim's suggestion, Sun-Woo manages to detach the lunar lander module from the command module in the nick of time. But the lander loses communications with Space Command back on Earth. Sun-Woo's life support system signal is also lost.

Meanwhile, Kim tried to contact his ex-wife, Yoon Moon-Young (Kim Hee-Ae), who was in a high position at NASA. Kim knew that NASA had their astronauts on the lunar gateway, and that they could help Sun-Woo and save his life. Moon-young wanted to help Kim, but there were clear directives from the government that they didn't want to provide any sort of assistance because of the political tension that had happened after the first Korean mission, which had led to Korea being taken out of the international space committee.

Everybody back in Korea believed that Sun-Woo had died, and even Kim had gone back to his place to drown himself in sorrow. But NASA knew that Sun-Woo was still alive as the lunar gateway had intercepted the radio messages that he was trying to send to his own space station.

Moon Young's conscience didn't allow her to just sit there and let a boy die when she knew that the astronauts could save him. She passed classified information on how to access a US Satellite to Kim, informing him that his son was pretty much alive. That's when Kim established contact with Sun-Woo and Han-Byeol (Hong Seung-Hee), his assistant uploaded that audio of San-Woo's voice, where he and Kim were conversing on YouTube. Sun-Woo informs Kim that his lander managed to land on the moon.

That small clip of Sun-Woo and Kim talking created waves on social media, and US citizens came forward in support of the Koreans and asked their own government to save the boy. US government knew that they didn't have any other option but to go ahead with the rescue plan. US grants Korea permission for the Woori-Ho to dock with the lunar gateway and the gateway is put into position to receive the landing module. But when Sun-Woo fires the rockets of his lander, the soft ground underneath gives way and the lander tilts and only skims along the surface of the moon.

All this while, Sun-Woo believed that it was because of his father (who was the 2nd designer of the spacecraft Narae-Ho) that the lives of those three astronauts, who were inside the Narae-Ho spacecraft, were lost. He told Kim that his father had left a letter in which he had written that he knew that there were some faults in the engine but had still gone ahead with the plan. That's when Kim had the big reveal and told Sun-Woo that his father was not guilty of anything, as he didn't want to go ahead with the mission. It was Kim who, even after knowing that there was a possibility that the spacecraft might explode, gave the green signal to the mission five years ago.

The possibility of an explosion happening was way too low, and after all the delays, Kim was just done waiting. He had lost his patience, and he didn't want to wait any longer to make Korea the second nation after the USA to carry out an expedition to the moon. Kim had left his job at NASA, and divorced his wife to come back to his own country, where he let the world know what he was capable of. He prioritized his country over anything else, and that's why, in order to prove his worth, he launched Narae-ho, though he realized that he should have listened to his colleague and not acted in such haste.

After listening to Kim, Sun-Woo felt like somebody had lifted a huge burden off his shoulders. He gets ready to once again try and go near that area where the United States of America had its lunar gateway. Kim and Moon-Young connect again on phone and Moon-Young tells Kim to fire the rockets again to get the lander into orbit to the near side of the moon, where the lunar gateway is located. She says that the angle of the lander now points in that direction, and only the rockets need to be fired.

Moon Young knew that the guards could come anytime and take her into custody, so she locked the room of her office and established contact with the astronauts who were there at the lunar gateway. She tells them that though there was no directive from the government, it was up to them if they wanted to go out there and save the boy and make the world believe that there was still some humanity left in them.

With Kim's help, Sun-Woo was able to achieve that feat. He doesn't manage to reach orbit but manages to land on the near side of the moon. The lunar gateway launches a rescue ship to pick up Sun-Woo from the surface.

As a result of undertaking such a daunting mission and coming out victorious, Korea was once again included in the International Space Committee, and the Korean president declared that he would share the findings of the mission with the entire world so mankind could benefit from them. Moon Young became the first female director of NASA, and Kim went back to his place to teach the young generation and motivate them to become space explorers and work for the betterment of their nation and mankind.