Grim mosaic portrait of the struggle in Afghanistan

Almost the first thing you see in Red Star Over Khyber (PBS, Tuesday Dec. 11, 9 p.m., check local listings) is a Russian soldier who has just been ambushed on a desolate dirt road in Afghanistan. The man is dying. And even at a considerable distance, one can see his completely uncomprehending expression - Where am I? How did I get here?

During this edition of ''Frontline,''chief correspondent Richard Reeves attempts to answer these questions.

Reeves is treading a road that many journalists have traveled. Behind-the-lines footage of rebel attacks on Russian convoys have become somewhat familiar on network news shows. What has not been familiar on television, and what Reeves attempts to give us, is a mosaic portrait of the incredibly complex mise en scene of international politics and ancient religious cultures from which this war has erupted.

A week before the five-year anniversary of the Soviet invasion, Reeves and his team show us the whole splintered mess of lives lost, ''damaged human beings ,'' thwarted Soviet intentions, morale and drug abuse problems in the Soviet Army, geopolitical card-playing by Pakistan's Zia ul-Haq, and the bleak outlook for almost everyone involved.

It may be in the nature of such an undertaking to fail in some respects, and this one has its failings.

The focus seems lost at times as the documentary veers from one subject to another, trying to cover all bases. Sometimes we breeze over subjects, such as Soviet involvement in the power struggles that preceded the invasion. Still, where this enterprise succeeds, it scores strongly - in bringing home a much more omnidirectional view of the quagmire and, especially, in giving us some insights into the experience of Russians here.

One walks away knowing more about the experience of Russian soldiers in this forbidding country. The papers of a slain soldier from Moscow, with reports that many conscripts thought they were coming to fight Americans, tell a story all their own. So do the pictures of tiny Soviet land mines, designed to maim instead of kill. Because they are disguised as pens or wrist watches, they frequently hurt children. One also looks closely at the stakes put on the table by Pakistan. Reeves's interview with President Zia is revelatory, especially in Zia's peculiar rationalization for press censorship.

In the end, ''Red Star Over Khyber'' brings the continuing struggle over Afghanistan before us with a good deal of immediacy.