George and his best friend, Annie, have been selected as junior astronauts, part of a program that trains young people for a trip to Mars in the future. This is everything they've ever wanted; they get to be a part of up-to-the-minute space discoveries and meet a bunch of new friends who are as fascinated by the universe as they are. But when they arrive at space camp, George and Annie quickly learn that strange things are happening, both on Earth and in our skies. Mysterious space missions are occurring in secret, and the astronaut training they're undertaking becomes scarier and scarier. This is the fifth adventure in the series by Lucy and Stephen Hawking, which also contains up-to-the-minute scientific facts and information from the world's leading scientists.