Four young math whizzes team up to solve a legendary puzzle
The Citadel of Aivirai is a fantasy world of towers, lakes, bridges, walkways and symbolical trees. In its heart is a school called the Queen of Science Academy, for children of extraordinary mathematical ability. They sleep in dormitories, eat at communal tables, wear colour-coded uniforms, and attend classes taught by mathematical geniuses of past eras. It's a magical place where maths is central to every part of their lives.
The children have no idea how they arrived in Aivirai. Their only recollections of the past come through dreams. They don't understand the concept of parents, or family. The teachers maintain their distance, and discipline is kept by older pupils who appear and disappear at will. Only the eccentric Librarian is reputedly willing to listen to their problems in between ferociously protecting the books which she none-the-less stamps on every page.
The children are introduced to mathematical puzzles in class and given others to solve out of class, but for one boy, Muko, this isn't enough. He overhears two teachers talking about a mysterious but immensely important riddle, and such is his thirst for adventure that he wishes to be the first to solve it.
He forms a small team with three other children and becomes their leader. Amartia, the least sociable of them, is the mathematical genius behind much of their progress. Paidia and Gelio, close friends and comical sparring partners, also bring their intelligence to bear at crucial moments.
The children's quest begins with picking the brains of the delightfully absent-minded Professor Hedgehog, then tricking Pythagoras into getting them past the Librarian's strict access restrictions to seek out an ancient volume. A series of complex mathematical hurdles later, they find themselves in peril of their lives.
What have our four friends let themselves in for? Will they prevail against the machinations of strange artefacts and sinister mountain caverns? Solving the many riddles will add an extra dimension of enjoyment to reading the book, but it is also a magical adventure story accessible to any youngster with or without a mathematical bent.