The protagonist is Nagatomo, an astronaut and scientist overseeing a covert operation involving cryogenic experiments on human subjects, such as assassins or political prisoners, aboard a spaceship named "RETRO." He suddenly awakens on the ship to find numerous black spheres floating in space outside. Initially suspecting they might be debris, he soon detects signs of life within them. He exits the vessel to retrieve one of the spheres, opens it, and discovers a girl inside named Kishimoto. Kishimoto and Nagatomo are then transported to a GANTZ room that resembles the one in Tokyo. The black sphere in the room plays a radio song, reveals the target—the "comedian alien"—and dispatches both of them to the battle zone. Kishimoto is now wearing her GANTZ suit, while Nagatomo remains in his spacesuit. They engage the aliens; Kishimoto proves useful due to her knowledge of the missions, and they are subsequently returned to the room. The "Astronaut" earns 6 points, while "Big tits" receives 0. Kishimoto chooses to remain in the GANTZ room, having nowhere else to go, whereas Nagatomo departs, promising to return.