'Twins Luke and Mark are inseparable; that is, until Mark mysteriously vanishes while kayaking down the Bandinangi River. Hauled into the future by shrouded ghost people, Mark is charged with being a vandal - an environmental thug. This is a society where even noise is considered a pollutant. Mark is in real trouble, especially when they start testing him to see if he has intelligence.'

Source: Trove.