Tropical island underwater scuba diving swimming murder thriller, in which divers and thieves search for a sunken treasure.

Freshly arrived Sandhurst-trained Captain Alan King, better versed in Pashtun then any of the veterans and born locally as army brat, survives an attack on his escort to his Northwest Frontier province garrison near the Khyber pass because of Ahmed, a native Afridi deserter from the Muslim fanatic rebel Karram Khan's forces. As soon as his fellow officers learn his mother was a native Muslim which got his parents disowned even by their own families, he falls prey to stubborn prejudiced discrimination, Lieutenant Geoffrey Heath even moves out of their quarters, except from half-Irish Lt. Ben Baird.