When thirteen year-old cousins Ivan and Daphne complain of boredom, their Aunt Adelaide sends them on a treasure hunt in a land where words and numbers run wild. Before they know it, they’ve taken on a pet thesaurus and the challenge of finding the Land of Lexicon’s lost children.
The cousins travel from village to village, solving challenges, befriending an unlikely lot of characters and gathering clues. When a careless mathematician transports them to the Land of Night, their danger deepens. They have to call on all their courage and creativity to battle kidnapping, imprisonment and blind deceit before they can solve the mystery of the lights in the sky and return the lost children of Lexicon to their homes.