But Paris loves Helen and will hear nothing of it. In the Greek camp, a mysterious plague has been raging for several days. Calchas the seer tells the assembled kings that Apollo sent it as revenge for Agamemnon enslaving the beautiful Chryseis, the daughter of a priest who complained to the god. Achilles demands that Agamemnon return the girl to her father. Agamemnon finally accepts but says that Achilles must give him his protégée, Briseis, as compensation. Seething with rage, Achilles swears that he will fight no more and goes into isolation. His mother, Thetis, goes to Zeus and asks him to defend Achilles. Remembering who he once loved, the mighty Olympian god decides to take the side of the Trojans and sends a dream to Agamemnon to set a trap for him.