George is heartbroken when he learns that his friend Annie and her father are moving to the US. Eric has a new job working for the space program, looking for signs of life in the Universe. Eric leaves George with a gift--a book called The User's Guide to the Universe. But Annie and Eric haven't been gone for very long when Annie believes that she is being contacted by aliens, who have a terrible warning for her. George joins her in the US to help her with her quest--and before he knows it, he, Annie, Cosmos, and Annie's annoying cousin Emmett have been swept up in a cosmic treasure hunt, spanning the whole galaxy and beyond.

Lucy Hawking's own experiences in zero-gravity flight and interviews with astronauts at Cape Kennedy and the Johnson Space Center lend the book a sense of realism and excitement that is sure to fire up imaginations. The book includes essays written by Professor Hawking and his colleagues, in which they provide the latest thoughts on space travel.