We live in an age of rampant faithlessness. Partners break their commitments to each other by having affairs. Prenuptial agreements signal a lack of trust between men and women. The growing use of surveillance technology by corporations to spy upon employees and the polished lies of politicians are two more examples. On the everyday level, it is almost impossible to find a service professional who will keep his or her word to show up for a job when promised.

When trust becomes a matter of doubt in human relations, something incalculable has been lost. This important ethical theme is richly explored in Faithless, a Swedish film directed by Liv Ullmann and written by Ingmar Bergman. Here an act of adultery casts a shadow of doubt, despair, regret, and pain on the lives of five people.

Bergman (Erland Josephson), an elderly writer who lives alone on an isolated island, is working on a script about a love affair in his past with a married woman. He summons his muse, Marianne (Lena Endre), to help him. Through the alchemy of imagination, she is transformed into the protagonist in the drama: Marianne Vogler, a successful actress married to Markus (Thomas Hanzon), a world-famous orchestra conductor. They have a nine-year-old daughter, Isabelle (Michelle Gylemo).

One of Markus's best friends is David (Krister Henriksson), a film director who is a perfectionist in his work but careless in his personal life. When Marianne gives in to his casual suggestion that they sleep together, neither of them is ready for the consequences. They begin an affair that leads to a secret trip to Paris together. Marianne, who seems to enjoy the danger of their tryst, is nonetheless taken aback by David's jealousy and volatile moodiness.

Liv Ullmann draws out a nuanced and affecting performance from Lena Endre, who is on screen for most of the two-and-one-half hour running time. The fallout from the affair and Marianne's act of betrayal is devastating, especially upon her husband and daughter. But the one who is most grievously wounded is Bergman, the writer of this story who must live with the guilt of having let down the one woman he truly loved. Reflecting on the past, trying to exorcise his demons, the writer only succeeds in plunging deeper into regret over his selfishness.