Dr. Wilhelm von Huber, a top NASA scientist recently relocated to Cape Canaveral with his 12-year-old son, Billy. Their relationship has become strained in the wake of the recent death of Billy's mother. Billy finds his father old-fashioned and boring. He wants to lead an exciting life, to be a hero like the young astronaut, Alan Shepherd. It's not long before Billy gets his chance. Billy is hired by Dr. Donni McGuinness, the beautiful Director of Veterinary Sciences, to help train the chimpanzees for NASA space missions. Billy begins to develop a close bond with one particular chimp -- Mac. With Billy's help and companionship, Mac is chosen to become the first American astronaut launched into space. It all seems like a wonderful game until Billy realizes that his new friend is preparing to be hurled hundreds of miles into orbit on his historic mission. Mac's big chance to explore the farthest frontier -- and hurtle America ahead in the race to space -- might easily cost him his life.