S4, E6: Astronaut Chris Hadfield stops by the Bookabus to share his new book, `The Darkest Dark': a story about how he dreamed as a boy of going to outer space. While watching the first moon landing, he discovers the unknown can be exciting. `Captain America' superstar Emily Van Camp also has a story that's out of this world: a book called `Harry and Horsie', written by her sister, about a little boy and his favourite toy.