Jim is the new boy in the class, he is 11 years old and passionate about science and especially space. At school, he has to collaborate with Emma in a science competition.
Although she is initially reluctant, Jim persuades her to copy her idol Joseph Kittinger, who was the first human to travel to the edge of space. Together, the two sixth graders embark on the secret project of building their own helium balloon to travel up to space.
Along the way, the most incredible situations arise that bring them closer together. Spaceboy is a mix of comedy, adventure and maybe even a little romance.