As the space race heats up in the early 1960s, NASA scientist Dr. Wilhelm von Huber is having trouble relating to his son, Billy, following the death of his wife. But when von Huber is hired by Dr. Donni McGuinness to help train a chimp named Mac for a special mission, things change between father and son. Billy bonds with Mac as the chimp prepares for his space flight, and in the process, he and his dad begin to better understand each other.