During the U.S. involvement in the Viet Nam conflict, Marine Captain Timothy Miller's F-4 Phantom fighter is shot down. On the ground in enemy territory, injured, Tim is soon captured. He is taken to an underground Viet Cong infirmary. There the wounded pilot is treated and held prisoner while waiting to be moved to Hanoi to be imprisoned. He encounters nurse Anh who cares for his wounds.While Tim is recovering, an airstrike on the tunnel system causes a massive cave in. As the dust settles it turns out that he and Anh are the only two survivors and find themselves trapped in the partially collapsed chamber. Through mutual need the two sworn enemies band together and dig their way out. Finding that the tunnels have been abandoned by her fellow soldiers, Anh and Tim are alone when they reach the surface and safety.In an act of kindness Anh decides to give Tim his freedom for helping her out of their underground tomb. The two spend the night in the jungle before she leads him to a nearby U.S. firebase and disappears from his life. Before parting Tim gives her his dog tag and makes a promise to her that after the war if she ever needed something to get in touch with him and he would do anything within his power for her.Thirty years later Tim finds himself retired and divorced. His wife and kids get the house in Atlanta. He packs up and moves to their beach house in Florida where he is originally from. He has a bittersweet reunion with his mother and father who also live in Panama City. He slowly picks up the pieces of shattered dreams and rebuilds his life.Then, early one morning Tim receives a fateful phone call that will change his life forever. It is from the Viet Cong nurse, Anh, who let him go free all those years ago. She is living in San Francisco and is calling in on the promise he made. Anh related that she urgently needs to discuss something with him but does not want to do it over the phone. Tim readily makes arrangements and flies out to see her. Anh is as beautiful as ever. He learns that she is a recent widow. Her husband had been a prominent physician there for many years. She then reveals that she has terminal cancer which saddens Tim. Then she tells him why she has called. He has a granddaughter in Vietnam who is now an orphan, her name is Nan. Anh is too ill to travel and asks Tim to go to Vietnam and get Nan out before she disappears or is sold on the black market. Anh has contacts that will covertly help Tim get Nan quickly out of the country. He agrees to the plan and the wheels begin to turn.