It is the year 2063 A.D. At her home, Aries Spring is preparing to leave for her five-day Planet Camp on Planet McPa for five days. At the Mousanish Spaceport, Aries' merry mood is interrupted when she accidentally spills the contents of her suitcase onto the floor of the terminal. As an elderly lady helps her gather her items, a thief riding a unibike suddenly grabs her bag; a young man wearing anti-grav shoes pursues the thief. The boy leaps over a fountain and lands on the thief, knocking him down and subduing him; he attempts to yell the words "anti-grav dive bomber" as he lands, purely for the sake of drama, but mispronounces the words horribly, embarrassing himself. As Aries thank the young man for his help, calling him "Mister Thigh Domber" after his misspeaking, the spaceport's security patrol-bots arrive and take him into custody, mistakenly believing him to have unjustly assaulted the thief.
Elsewhere in the spaceport, the rest of the Planet Camp group has already assembled. The man in charge, noting that two of the students are missing, marks their absence as a bad omen as Aries runs up to join the group at last; she enthusiastically introduces herself to them as someone who never forgets people she has met. The man then addresses the kids about the particulars of Planet Camp: being dropped off on another planet for five days and enjoying the experience without the intervention of adults. He introduces two of the students as Quitterie Raffaelli and her younger sister Funicia, explaining that their task while on McPa will be to act as caretakers and teachers for the girl. When Aries notes that one of them is still missing, the young man who retrieved her bag for her arrives, being carried by the patrol-bots. He introduces himself as Kanata Hoshijima and boldly states that he will be the captain of their group. None of the others in the group are pleased by his brashness, but he seems not to understand why. He is especially perplexed by Funicia's Beego toy, a hand puppet that voices her thoughts toward him in the voice of an old man, betraying that she views his behavior as puerile.
Sometime later, the group boards a spaceship and departs for Planet McPa. As the other students ask the man questions about what they can do to pass the time, Aries thanks Kanata for helping her out at the spaceport, giving him a frozen tangerine in thanks. She asks Kanata what made him want to be the captain, and he replies that being an explorer with his own ship and crew is a childhood dream of his. He mentions that a person he was close to passed away, and he wants to carry on that person's dreams. Moved by the tale, Aries enthusiastically promises to cheer him on, believing that his dream will come true someday. She then offers him barley tea; her behavior strikes Kanata as oddly grandmotherly.
After four hours of faster-than-light travel, their ship successfully lands on Planet McPa; the students step from the ship onto the surface, and the ship departs, leaving them alone. Seconds after the ship's departure, however, a large, glowing orb materializes close by. A boy named Luca Esposito is the first to notice it and calls it to the others' attention; as the orb, emitting a low, resonating sound, moves toward the group, Luca steps between them, confident that there is nothing to be scared of. The moment it touches his outstretched hand, to his horror, it begins drawing him into itself; seconds later, he is gone, completely swallowed by the orb. Kanata yells for them all to reactivate their bubble helmets and run, but the orb pursues them, swallowing every single one of them. As Kanata is pulled into the orb, maddening streaks of light flash past him, and he tumbles, helpless and confused until he suddenly finds himself floating in orbit above a planet wrapped in clouds.
He quickly discovers the others are all there with him as well. As they assess their situation, Luca speaks again, drawing their attention to a ship floating a short distance away. They grab their floating luggage and maneuver themselves to the ship using their crust suits' gas thrusters; finding it abandoned, they board the vessel. Once past the airlock, Zack Walker, realizes that Aries is not with them; she is still floating in the vacuum, with her suit's communication system damaged and her thrusters malfunctioning. Kanata, experiencing a flashback of the moment his teacher died, refuses to accept defeat and volunteers to rescue Aries himself. He attaches a metal cable to his crust suit's pack and jumps into the void to retrieve her, but he runs out of cable before reaching her. Still dissatisfied, he unclips the wire, reaches Aries, and maneuvers back to the end of the cable, clipping himself back on and allowing the others to reel them back into the ship.
Back on the ship, Aries emphatically thanks Kanata for saving her life. Kanata suggests that they contact their school to inform them of their misadventure, but Zack tells him and the group that the ship's radio is missing parts and non-functional. Further compounding the bad news, he reveals that they are not in orbit around McPa; instead, they are 5,012 light-years away from McPa, in orbit around an unknown planet, and declares the chances of their being rescued to be zero. Aries begins keeping a camp journal, recording that their first day of Planet Camp began with them becoming stranded in the far reaches of outer space.
- Aries Spring
- Emma Spring
- Quitterie Raffaelli
- Luca Esposito
- Yun-Hua Lu
- Kanata Hoshijima
- Funicia Raffaelli
- Ulgar Zweig
- Zack Walker
- Charce Lacroix
- Kanata's Teacher (flashback only)