Alice Dare, having survived Mars Evacuees, has written a book about her experiences and has gained some renown as a "plucky kid from Mars". When she has an opportunity to visit her friend Thsaaa's home planet (The Morrors have an Earth colony in the Swiss Alps, where it is nice and cold!) with her friends Carl, Noel and Josephine, she's very excited, but her parents aren't. Her father doesn't want her traipsing around the galaxy, and her mother is called away to deal with a Vshomu infestation. When her father becomes ill, she manages to get on the space elevator and boards the Helen of Troy, Ramus Trommler's luxury ship. Things go well until the ship is attacked by Krakkilluks, lobster-like creatures who have no use for "spawn", so throw Carla and Alice out of the space ship when they get lippy! Luckily, Josephine jumps after them and brings the Goldfish, and the group manages to crash onto the moon that is an article of contention for the Krakkilluks. They are angered that Dr. Muldoon has been terra forming it for eventual use by the Morrors; the Krakkilluks are using it for their own purposes. Stuck on a strange planet that is warm but has too much oxygen, the group tries to befriend local life forms with the help of the Goldfish's translating skills, and uncovers information about various plans to attack Earth. Will Alice be able to make it back to the ship to alert someone about these plans, or will she and her friends get stuck on the moon as slaves?
The world building in this book is spectacular, especially when it comes to alien languages. I am usually annoyed by made up languages, but both the Morrors' and the Krakkilluks' languages are carefully crafted to go along with the sort of creatures they are. It's also impressive that McDougall is able to be more imaginative with the alien life forms-- Thsaaa's people have five genders and their moods are expressed through the color of their skin; they are also very sensitive to heat. The Krakkilluks' language is "crunchy" and goes along with their crab-like appearance; their insistence on speaking with a married couple is funny, but also shows that culture is not the same for all races. Their disregard of "spawn" leads to most of the adventure, and I loved the scene where the Earth dwellers just can't believe that the Krakkilluks are willing to dispose of the children without even blinking!
Alice's troubles with Josephine, as well as Josephine's own difficulties, add a more serious note to the book, but the Goldfish is one of the best comic relief characters I've come across. If you are looking for an interplanetary romp with amusing characters and vivid world building, definitely pick up Space Hostages... just remember to bring your own duct tape!