Synopsis
The opera is set on the Island of Crete, shortly after the Trojan War.
ACT I
Ilia, daughter of the defeated Trojan King Priam, expresses conflicting emotions – love for her rescuer Idamante, son of the Cretan King Idomeneo, and hatred for her father’s Greek enemies. Idamante frees the Trojan prisoners in a gesture of good will. Trojans and Cretans welcome his action, but Elettra, daughter of the Greek King Agamemnon, does not approve of Idamante’s clemency toward the enemy prisoners. Arbace, the King’s confidant, brings news that Idomeneo has been lost at sea while returning to Crete from Troy. Elettra, sensing Idamante’s love for Ilia and fearing her Trojan rival may become Queen of Crete, invokes the furies of the underworld.
In a storm at sea, Idomeneo is saved from drowning by making a vow to Neptune (God of the Sea) to sacrifice, once safely on land, the first living creature he should meet. Idamante comes looking for his father. When Idomeneo realises the youth that he must sacrifice for the sake of his vow is his own child, he orders Idamante away from him. Idamante is griefstricken by his father’s rejection. The Cretans praise Neptune for Idomeneo’s safe arrival home.
ACT II
Idomeneo seeks counsel from Arbace, who suggests sending Idamante into exile to avoid the sacrifice demanded by Neptune. Idomeneo orders his son to escort Elettra to her home, Argos. Ilia declares her allegiance to Idomeneo; since she has lost everything, he will be her father and Crete her country.
Idomeneo’s realisation that Ilia has feelings for Idamante further deepens his sorrow. Euphoric, Elettra welcomes the prospect of going to Argos with Idamante as her betrothed. At the port of Sidon, Idomeneo bids his son farewell. Before the ship can sail, a great storm breaks and a sea monster appears. Recognizing it as a messenger from Neptune, the King offers himself as atonement for having violated his vow to the God.
ACT III
Ilia asks the breezes to carry her love to Idamante, who comes to farewell Ilia before he leaves to prove himself by killing the sea monster – he would rather die than suffer the torments of his rejected love. Ilia confesses her love for him. They are surprised by Elettra and Idomeneo, who refuses to explain why he rejects Idamante. Arbace grieves for Crete, now in the grip of crisis. The High Priest tells the King of the destruction caused by Neptune’s monster, urging Idomeneo to reveal the name of the sacrificial victim demanded by the God. When the King confesses and names his own son, the populace is horrified.
All pray that the God may be appeased. Arbace brings news that Idamante has killed the monster, but Idomeneo fears new reprisals from Neptune. Idamante enters, ready to die. After an agonising farewell, Idomeneo is about to sacrifice his son when Ilia intervenes, offering her own life instead. The Voice of Neptune decrees that Idomeneo must yield the throne to Ilia and Idamante. Thwarted again, Elettra rails against her fate.
Idomeneo presents Idamante and his bride as the new rulers as the Cretan people celebrate.