Chryses comes to ask their leader, King Agamemnon, to release his daughter, whom Agamemnon was holding captive. When Agamemnon refuses, Chryses prays to the Apollo to send a plague against the Achaians.
After many days of 'plague', the Achaians demand that Agamemnon give Chryses his daughter back. Agamemnon eventually agrees, but on one condition. He will get to take Brises, Achilleus's girlfriend. (Achilleus is known to be the best Achaian warrior.)
We will win!
Even though Achilleus gives his girlfriend up, he becomes very angry and he refuses to fight any more. He then prays to his mother, Thetis, who is the goddess of water, to try and make the Achaians lose in battle so that they will realize how much they depend on him.
I would like to fight.
Achilleus's mom gets Zeus to agree with her son's request.
The next day the Trojans make a successful counterattack, led by Hektor, their greatest warrior.
Achilleus's best friend Patroklos asks for permission to go into battle in Achilleus's place. Achilleus allows him to, and even lets him wear his armor.