"Noon Wine," the "American Playhouse" offering tonight at 9 (Channel 26) confronts the question of truth in a world where ambiguities are inconceivable, and the inability of simple people to accept them ultimately destroys the moral center of their lives.

Based on a story by Katherine Anne Porter, "Noon Wine" is set in South Texas in 1896, on the scruffy farm of Royale Thompson (Fred Ward), who thinks that milking cows is "women's work." A taciturn and mysterious stranger arrives looking for work -- the Swede Olaf Helton (Stellan Skarsgard). His extreme withdrawal, not to mention the odd way he kills chickens by snapping their necks with a sharp throw, would flag him as a potential psychotic in these days, but the Thompsons think he's just a different kind of guy.

Whatever his oddness, he saves their farm, and for nine years the family and hired hand prosper. But then a man (Pat Hingle) arrives looking for Helton, saying the quiet Swede is an escaped lunatic who killed his own brother, another twist in a sad and desperate tale, with a slowly realized impact.

Michael Fields, who wrote and directed "Noon Wine," (and submitted the script to "American Playhouse" over the transom), has painstakingly created the thousands of small details of a desolate hard-scrabble farm. The atmosphere, like the melancholy tune the Swede plays on his harmonica, is haunting. The actors, notably Ward and Skarsgard, are superb, although their lines are occasionally so naturalistic they are inaudible.

Only the ending leaves one somehow dissatisfied with what seems an easy way out, a short cut to resolution. But the story and the people linger, a reminder of how a shadow of doubt can darken a whole life.