The human cost of war is high, often measured not by who dies, but who lives.

Rarely is that poignant message driven home so affectingly, so powerfully as in "Miss Saigon," the national tour playing through June 13 at the San Diego Civic Theatre.

Written by Alain Boublil and Claude-Michel Schonberg, with music by Schonberg and lyrics by Boublil and Richard Maltby, Jr., it is simply a remarkable piece of theater, a show for the ages. Directed by Mitchell Lemsky and choreographed by Jodi Moccia, the acting is spectacular, the voices memorable, the music stirring, the special effects astounding, but at its core is the heart-rending story of love and loss, of things that must be and things that can never be, where everyone deserves to win and no one will. It tears at your gut and your conscience, long after you've left the theater.

Inspired by "Madame Butterfly," it tells the story of the final days of Saigon in war-torn South Vietnam, as it was then known, and an unlikely burgeoning love between an American Marine and a young Vietnamese girl that was never meant to be.

Kim (Jennifer Paz) is a 17-year-old war orphan who flees to the city to avoid the same fate as her parents. Naive and innocent, she takes employment as a bargirl who is expected to serve up drinks and sexual favors with the same ease. Military buddies John (D.J. Oliver) and Chris (Alan Gillespie) are out on the town to get drunk and more. Chris ends up spending the night with Kim, a gift from John. Awakening, he realizes, as he gazes at the fragile, sleeping waif, that this will be his best memory of Vietnam. He determines to spend his remaining time with her.

But this is war, where time is measured by a different standard. Saigon falls. History's largest airlift is under way. Chris and his fellow Marines are being evacuated. Those Vietnamese lucky or wealthy enough to have gotten visas grasp at the opportunity to board the never-ending stream of choppers. Tens of thousands grasp at the solitary hope. Only a small percentage will be rewarded. Mass confusion ensues.

Where is Chris? He promised to take me.

Where is Kim? I promised to take her.

Life must go on, but neither ever forgets. Now married, Chris is stunned to learn Kim is still alive and has a son, their son. He returns to meet destiny.

Rarely does everything come together so perfectly to create such an unforgettable theatrical experience. The lightning speed at which the impressive sets, designed by Adrian Vaux, melt away and reappear under cover of Charlie Morrison's superb lighting design is poetry in motion, and Lucas J. Corrubia Jr.'s sound design puts you there, with a marvelous orchestra conducted by Kevin Casey frosting on the cake. (One of the best-known elements of "Miss Saigon," as seen on Broadway and in the last national tour to visit San Diego, is the use of a large helicopter mock-up in the fall of Saigon scene. In this tour, the helicopter is realistically depicted with sound effects and a large holographic video projection.)

Paz, the night I saw it, and Gillespie create magic, with emotions so achingly real, they hurt. Through splendidly executed song, a touch, a look, we live vicariously through these two, feeling what they feel, nonjudgmentally, hoping against hope.

Oliver, too, brings clear-eyed humanity to an impossible situation, his scruples piercing through the grayness, where nothing is black and white. The Engineer, as he is called, is the Eurasian wheeler-dealer who first introduces Kim to her new life of degradation. He's willing to be anyone's friend if there's something in it for him. Jon Jon Briones, who originated the role in London, is simply brilliant, giving a truly memorable performance.

This is just such a stunning artistic achievement, filled with inspired performances and direction. In every scene, in every song, the bells of honesty peal true in this most moving, human drama. It reverberates still.