Green Boy 1st edition

Long Pond Cay, in the Bahamas, is a magical white-sand island, and twelve-year-old Trey and silent seven-year-old Lou love to visit its loneliness. But one day the magic becomes nightmare, and suddenly they are in another world, strident, polluted, and overcrowded -- where little Lou is hailed not as a mute Bahamian boy but as the mythic hero Lugh, born to bring terrible destruction and renewal.
Carried betwween worlds in a zigzag adenture of mounting tension and danger, the children risk their lives not only to save the alien world, but to ward off a new, parallel threat to their beloved Long Pond Cay. The forces of myth and nature explode together in an amazing climax.
This is a deeply moving fantasy told by an internationally acclaimed Newbery Award -- wining writer, who knows and loves the Bahamian islands. Its vision of a spoiled world ominously like our own will haunt the reader for long time to come.