In the royal garden, Ilia asks the gentle winds to carry her love to Idamante. Idamante says he must go to fight the serpent. When he says he would like to die because Ilia does not love him. This makes Ilia tell him that she loves him. They are surprised by Electra and Idomeneo. When Idamante asks his father why he sends him away, Idomeneo cannot tell him the truth. Ilia asks Electra for some kindness, but Elektra is madly jealous of Ilia now, and she wants revenge. Arbace comes with news that the people, led by the High Priest of Neptune, are shouting that they want Idomeneo. The High Priest tells the king that Neptune's monster is destroying things, and asks Idomeneo to say the name of the person whose sacrifice is demanded by the god. When the king says that his own son is the victim, the people are horrified. 