In the one-act opera "Amber," by Alexandria composer Richard Rose, which had a concert performance Saturday at the Lyceum, a hero of World War II, 90-year-old retired Gen. Harry Goss, is celebrating Thanksgiving with his three aged offspring and recalling the horrors he witnessed and endured on the island of Bataan.

His daughter Amber wants to tell him a story she has kept secret for more than 50 years; her brother, Rusty, opposes the idea: "I wish you wouldn't dwell/ On things so long ago,/ On stories we should never tell."

While his daughter Jenny, a pianist, plays an old love song (Tommy Dorsey's "Getting Sentimental Over You"), Harry reminisces about his loving wife, who died in an automobile accident while he was at war.

Finally, Amber cannot keep the secret any longer. For two years, while he was away, she tells her father, his wife--her mother--had an affair with his brother: "They didn't hide it . . . / Their every embrace/ Wished you to die." And as an act of love for their father, she and Rusty arranged for the illicit lovers' death on a slippery mountain road: "Father, we did this for you . . . / To bring you back to us/ To bring you home." The shock of this revelation kills the weak old man.

Hearing this opera for the first time, one begins by wondering whether the sordid story is based on reality. A cryptic clue comes in a note at the end of the libretto that, "any resemblances of characters or story to any except those of an ancient Greek military family are coincidental."

Then one might reflect that the name "Amber" is a precise translation of the Greek "Elektra" and that the nickname "Rusty" has a family resemblance to the Greek Orestes, and it becomes clear that Richard Rose has fashioned a new variation on the ancient myth of Agamemnon, his wife, Clytemnestra, and his children Elektra and Orestes. It is a myth about a deeply dysfunctional family that fascinated the Greek tragedians Aeschylus, Sophocles and Euripides, modern German composer Richard Strauss and American playwright Eugene O'Neill. The saga of betrayal, violent death and revenge has lost none of its power in the course of more than two millennia.

Rose has taken liberties with the traditional tale; usually the death of Agamemnon has happened before the curtain rises or very early in the plot, and the focus of the action is on the children's bloody revenge. It is interesting to see a variation in which Agamemnon has survived and knows nothing of his wife's betrayal and the punishment she incurred.

The old story takes on new life in Rose's treatment, with dramatically apt music to control the pace of the performance and energize the text. It is cleverly constructed to be performable, as it was in the Lyceum, on a plain stage without scenery, costumes or props, with a piano (eloquently played by Barbara Wilkinson) serving as the accompaniment.

Only four singers were needed: mezzo-soprano Allison Baker in the title role, bass Graham Clark as the father, soprano Melinda Titus French as Jenny and the composer (who is also a proficient tenor) as Rusty. All did justice to their roles, and anyone who would like to see a fresh treatment of this timeless story will want to attend the repeat performance at the Lyceum on Aug. 15.

"Amber" was produced by Marginal Notes, a company operated by Rose to sponsor performances for the benefit of worthy causes. Its Web site (www.marginalnotes.com) has information about its activities and many of his other works.