The story recounts the final Apollo mission, Apollo 17, during which astronauts Jack Schmitt and Eugene Cernan spent 75 hours on the Moon. They conducted experiments and explored the lunar surface using a rover. As Commander Cernan prepared to leave, he made history as the last human to walk on the Moon. The narrative shifts to a broader discussion on the nature of moons versus planets, with Pascal Lee explaining that a moon orbits a planet, whereas a planet orbits a star.