Love And Deepspace: Xavier - Shooting Stars
The story of Xavier begins when he secretly meets the new 'un-crowned' queen of Philos — who is actually the MC. Xavier, his Grandis Knight, is preparing to embark on a mission with the Backtrackers to return to the past. The MC, who understands that Xavier's mission must be kept secret, says he has been considered dead to the kingdom.

After the MC tells Xavier that he will announce his brave sacrifice, he suddenly realizes that Xavier hasn't called him by his name in a long time. It's nostalgic, he glances at the star decoration on his sword. Then, he starts to remember their times at the Astria Knyght Academy.
In his memory, the MC is eagerly waiting for the return of the prince regent, Xavier, from the Starhunters space mission. He approaches Jeremiah, the vice-captain of the Starhunters expedition, and asks where the prince regent, Xavier, is.
Jeremiah tries to conceal Xavier's whereabouts, wanting to distract the MC so he won't search for him in his secret place atop the academy clock tower. The star-shaped sword tassel appears again, and the MC realizes that Xavier is looking at him with longing.
The MC remembers that a few months ago, Xavier suddenly disappeared even though the academy had reminded all students to always report their whereabouts because of the increasing Wanderer activity. During curfew, Xavier joined the Starhunter expedition and fled to the stars without telling his family anything.
The MC has kept all this a secret, not wanting to tell his family where Xavier went. He had asked about the tassel on his sword, but Xavier always avoided his questions. Instead of explaining who gave him the tassel, Xavier asked the MC for help and invited him to meet the following afternoon.
Xavier and the MC pretended to be the enemy prefects and rivals for the last Lightseeker position. They then staged a duel at the square, and Xavier had arranged for the MC to win.
During the duel preparations, Xavier revealed that he intentionally lost so that he wouldn't have to return to the royal family and face his father, with whom he had a strained relationship. He even said he hoped the king wasn't his father at all.
When the MC was about to strike and could have injured Xavier, the royal guards immediately separated them and dragged Xavier away. However, it was the MC who was hurt because he twisted his ankle after the fight. Jeremiah found the MC and told him that Xavier was upset because the royal family was discussing his marriage arrangements.
Both Xavier and the MC are trained by the same swordsmanship instructor. The MC is being specially trained to become a Grandis Knight, protector of the prince regent. But Xavier confessed that he is not sure he will sit on the throne because he doesn't want to at all.
The thought of the MC becoming a Grandis Knight for someone else makes Xavier uncomfortable. He doesn't want the MC to swear loyalty to anyone but him. He plans to reject the crown and asks the MC to give up in order to join the Lightseekers.
In return, he invites the MC to run away together to Uluru, a new planet he discovered on his last expedition. He says if he can avoid being crowned king and the MC also gives up becoming a Grandis Knight, he wants to escape together to Uluru.
The next day, Xavier prepares to meet his father at the royal palace. Before he leaves, the MC asks again who gave him the star-shaped tassel. Xavier finally admits that it was from the woman he loves more than anything, but unfortunately, she left him years ago.
He tells the MC that he is not sad, even though he has reunited with his lover; he has no memory of her at all. They talk for a while, and the romantic tension between them is very palpable. Without needing to say it, it is clear that they are in love with each other. After that, Xavier goes to the ceremony at the palace.
But, unlike usual, this time Xavier does not return at the time he promised the MC. No one knows where he went, and their teacher refuses to discuss it. The MC continues his training and successfully passes the Lightseeker exam, the next step in becoming Xavier's protector.
During Xavier's absence, the King dies. The kingdom announces that after a 200-year mourning period, a successor will be chosen. Those two hundred years feel bleak without a king. The knights have no place to pledge loyalty and have split into squads all over the world.
The MC continues to train to become the best knight he can be, determined that if Xavier ever returns, he will be there by his side again. In the meantime, he has Jeremiah by his side, the only person he can still talk to about Xavier, although Jeremiah's view of the prince has been tainted by his absence.
On a mission to the Starfall Forest, the MC leaves his group at night, distracted by illusions in the forest. He thinks he sees Xavier and runs to the heart of the forest, where he falls into a strange pocket dimension filled with stars. He thinks he is going to die until the real Xavier appears and saves him from the darkness.
Xavier says he has been in the Starfall Forest all along, trying to hunt the Wanderers that keep appearing there after being cut down. The two seem awkward with each other, reflecting on the time they have spent apart, but it is clear they still love each other.
However, when the MC asks more about what has happened during their separation, Xavier keeps diverting the conversation. Eventually, the MC — with Jeremiah's help — pretends he has been having seizures since escaping the forest illusion. Xavier instantly becomes worried and takes the MC to his spaceship to be treated.
Feeling guilty, the MC finally reveals that he has been pretending to be ill to get clues about what Xavier is hiding. He then informs Xavier that he has discovered the secret that Philos has been hiding all along.
The MC learns that Philos is a hollow planet built by humans. Unfortunately, the planet is slowly dying because its core has run out. Xavier also knows that because the humans on Philos are almost immortal, the planet absorbs their energy to stay alive.
Moreover, the side effect of this energy transfer is the emergence of Wanderers. Xavier had discovered all this during his Gladius Ceremony. He realizes that the Wanderers in the Starfall Forest were once humans, and their Protocore used to be human hearts.
The royal family has been sending humans to the Starfall Forest for hundreds of years to keep the planet alive. Xavier sees this practice as very abhorrent. But when he returned to the palace before his father died, he learned that the royal family had found the perfect sacrifice to recharge the planet: a girl who can be reborn endlessly.
The Titulus Ceremony was meant as the final sacrifice. Xavier must take the MC to the center of the Starfall Forest so that she can be thrown into its heart and die, then be reborn continuously for the planet to survive. But he refuses to partake in the ritual.
Xavier has created the Backtrackers to seek alternative solutions to the planet's energy problem, not just to save the planet but also to save the woman he loves more than anything. That woman is the MC, whose heart can be sacrificed endlessly for the planet's survival.
Understanding the importance of this mission, the MC promises to stay and reign as his substitute. She will become the queen to protect the people they love while she finds a way to save them.
Xavier vows to reunite with the MC when she becomes queen, and this time he will be her knight.