The Ruby Key takes place in a fantasy world inhabited by humans and nightlings. Humans rule the day and Nightlings rule the night. When Gennadara (Genna) and her younger brother, Danrith (Dan) venture into the forest at night to collect Taandu sap to make an elixir to heal their sick mother, they never imagined where it would lead them. They never thought they would be brought to Arrienda, the home of the Nightlings or even be friends with a Nightling. They never expected they would have to make a bargain with Kai-Lord Letrin of the Nightlings to save themselves and their family and all the villagers from the evil of Caer Banris who had already made a bargain with the Kai-lord for immortality (at the expense of Genna, Dan and the rest of their family). They never thought they would travel the moonroads or that they would travel them with a talking cat to find and bring back that which the Kai-Lord requested in order to fulfill their bargain. I really enjoyed reading this YA fantasy adventure quest by Holly Lisle. The story was very imaginative and engaging. The main characters, Genna and Dan, were not only likeable but honorable. There were themes of courage, honor, friendship, determination, loyalty, and respect that set a good example for young readers. There were enough twists and turns to keep it interesting and some mysteries yet to be resolved. Some things are settled at the end of the book but others remain open to be continued in the next book in the series, [b:The Silver Door|6261200|The Silver Door (Moon & Sun #2)|Holly Lisle|http://ecx.images-amazon.com/images/I/512FbjX9RaL._SL75_.jpg|6444408].