The Depths of the Sea by Jamie Metzl

It's 1979 and Morgan O'Reilly, a dispirited CIA desk officer, is desperately trying to bury his memories. Sent to Cambodia as a Marine and then as a CIA operative during the Vietnam War, he had been given the unlikely task of pulling together a secret spy unit of orphaned street children. At the end of the war, he was only able to get one child out of the country, his surrogate son, Sophal. Years later, Sophal, now a CIA agent, disappears on a secret mission in the Cambodian refugee camps in Thailand.

Tom Dillon, the dashing young superstar of the White House foreign policy staff, asks O'Reilly to find Sophal and bring him home. O'Reilly's search takes him deeper and deeper into the politics of the Thai-Cambodian border and finally into the deadly Khmer Rouge zone - a place where all foreigners are forbidden from entering and where cruelty and death are omnipresent.

Filled with the fascinating workings of the refugee camps, the life or death politics of Washington, DC, and the inner workings of the personalities that are drawn to such extreme circumstances, The Depths of the Sea is a thriller that both entertains and educates.