Menelaus understands that Paris has kidnapped Helen. He asks his brother Agamemnon, the king of  Mycenae, for help. Agamemnon gathers all the Greek kings and heroes in the temple. He accuses Troy of treason, and demands the Trojan to account. He orders the Greek heroes Achilles, Odysseus and Ajax to be ready for a war with Troy. His aim is to attack Troy as soon as possible, invade this country and avenge his brother. He consults Priest Chalcas for future telling. The priest advises him to make a sacrifice to the goddess Artemis for a victory. Agamemnon's daughter, the young princess Ephigenia is brought to the alter accompanied by rituals.