Eli "E.J." Mackernutt Jr., Michael Link is an 11-year-old boy in Titusville, Florida who dreams of traveling beyond Earth. His best friend Joey Williams, Stephen Rogers, helps him sneak into the nearby Kennedy Space Center, dressed in a makeshift hard hat and security paraphernalia, carrying a toolbox as if he belongs there. The two boys slip past the workers and hide inside a trash compartment in the command module Camelot atop the Saturn V rocket, waiting for the crew to arrive for the scheduled Project Apollo flight to the Moon. When a last‑minute overweight reading is logged—an 87‑pound discrepancy that no one can fully explain—the team decides not to delay the launch, and the countdown continues. Meanwhile, Eli Sr., Edward Faulkner, discovers a note from his son and rushes with his wife Mary Mackernutt, Barbara Faulkner, to the Kennedy gates, pleading with the staff to reveal that E.J. has stowed away. But the gate staff remain unconvinced.
As the rocket launches on schedule, the crew gradually becomes aware of the stowaway, and command module pilot Ben Pelham, Jim McMullan, eventually notices the unexpected presence. Through a series of flashbacks, E.J. recounts how he and Joey were building a large-scale model of a space capsule to fund a bigger project, and how their work with Jacob Avril, the property owner near the Space Center, gave him the idea that a Moon visit could be within reach. Avril, John Carradine, looms large in E.J.’s plan owing to his close proximity to the launch site, and E.J.’s longing to meet real astronauts becomes a driving force behind his audacious stunt.
The mission continues despite the stowaway’s presence, with flight director Charlie Englehardt, Lloyd Bridges, weighing the risks and the public’s reaction. The principal investigator urges keeping the mission alive because the Moon mission would be the only planned visit to Rupes Altai on this flight. E.J. apologizes on live television for his actions and asks that his stunt not jeopardize the crew’s vital work. Englehardt, recognizing that the boy has captured the public imagination—and perhaps even the President’s attention—reluctantly approves proceeding with the Moon landing.
Once in lunar orbit, the crew begins undocking from the command module and prepares to descend. The team includes Rick Lawrence, Jeremy Slate as the mission commander, and Dave Anderson, Morgan Paull as the lunar module pilot. E.J. helps tidy the cabin with a vacuum cleaner and takes on chores to keep the environment calm. He notices Pelham’s illness, but Pelham insists it is a mild case of space adaptation syndrome and asks E.J. to say nothing to the others. As Lawrence and Anderson detach in the Lunar Module Little Dipper, Pelham’s condition worsens, and a crisis unfolds.
When a malfunctioning valve causes a dangerous loss of oxygen, the crew relies on E.J.’s resourcefulness. He remains brave, retreating to Little Dipper to conserve life support while the others in spacesuits press on. In a tense sequence, the young observer helps locate the Lunar Module, which lands far off course, and the team manages a risky return to the command module with a Genesis Rock in tow. Without E.J.’s quick thinking and steady presence, Pelham might not have survived, and the lunar rendezvous could have failed, sealing a tragic outcome for the mission.
Back on the home planet, the story returns to Earth where the boy, Joey, and Avril watch the Moonrise from Avril’s property. The crew’s successful return is a tribute to E.J.’s unwavering faith in space travel and his belief that human curiosity can bridge the gap between dreams and reality. As the Moon glows overhead, the team acknowledges the boy’s impact on their voyage home, a sentiment captured in their final words to him.
> Kid, you got us off the Moon. Without you we'd be part of those rocks and rilles down there forever and ever! Now we're going home, and we've got you to thank for that!
