Greenstone Mystery

"Greenstone Mystery is the adventure of six children from New Zealand who are suddenly transported back in time to an ancient land. A strange looking man appears and tasks them with solving a puzzle that has faced mankind since the beginning of time - what is the most important truth in the world? Guiding them on this quest is a compass in the form of a greenstone pebble, given as their only hope of reaching home safely. They must first collect all the clues along the way, to finally unravel the Greenstone Mystery and discover the truth."--Back cover.