"It is impossible to suffer more," sings the quartet at a climactic point in Mozart's "Idomeneo," and that fairly well sums up both the opera and its performance history. After 201 years, "Idomeneo" finally had its first production at the Metropolitan Opera late last year, and will reach a national television audience tonight at 8 on Channel 26, with stereo simulcast on WETA-FM (90.9).

Reactions will be mixed; "Idomeneo" is a treat for connoisseurs, not a light evening's entertainment for the casual viewer. It is the first opera of Mozart's maturity, quite different in tone and style from his better-known works. It is an opera seria--a form that was already moribund in Mozart's time--and he was able to revitalize it musically but not to do much with the silly, archaic plot. If it were not for the music, it would be hardly worth tuning in tonight. But the music stands on the threshold of greatness and frequently breaks through.

The plot is dominated by the wrath of the sea god Neptune, whose face in a bas-relief several stories high dominates the stage setting by Jean-Pierre Ponnelle. Neptune, a partisan of the losing side in the Trojan War, catches one of the winners, King Idomeneo (Luciano Pavarotti) in a storm at sea on his homeward trip. To avoid shipwreck, Idomeneo has to vow to sacrifice the first person he meets when he reaches land--who turns out to be his son Idamante (Frederica von Stade). There is also a love triangle between Idamante, Elettra (Hildegarde Behrens) and a captive Trojan princess, Ilia (Ileana Cotrubas), and a happy ending is achieved only after Idamante slays a sea monster sent by Neptune to devastate Crete and the god finally relents his fury. The glorious music linked to this hopeless plot is (with a few exceptions) superbly sung.

The chief surprise of the production is Pavarotti's grasp of Mozart's style. He is in excellent voice until near the end when signs of fatigue crop up, and he uses all three of his facial expressions eloquently. Cotrubas and von Stade both sing gloriously, and the supporting roles are well-filled, particularly by tenor John Alexander. Behrens is excellent whenever she has to appear enraged or distraught, which is most of the time, but in her few quiet moments the voice is a bit thin and shaky.