Chryse, priest of Apollo, reached with precious gifts the Greek camp to ransom her daughter Chryseis, that had been captured and she is enslaved of Agamemnon . When Agamemnon sent away Chryse refusing the ransom, the old priest invoked the revenge of Apollo that  immediately come. On the Greek camp rained the poisoned arrows of Apollo and it was a massacre of men and animals.
Achilles convened the Greek in a meeting: in that venue, the diviner Calchas revealed the reasons for the deadly plague that had struck the Greek camp and solicited the restitution of Chryseis to her father, without ransom and with an expiatory sacrifice. Agamemnon, even though furious, was prepared to return Chryseis, but demanded for himself in change another reward, because didn't happen that him only, among the Greek, remained without his part of the war booty. Achilles replied that that was impossible: the whole war booty had already been divided, neither it could be taken off from the others to give it to Agamemnon; he would have had his reward, multiplied, when Troy would have been taken and sacked. That brought among the two a furious quarrel: they exchanged insults each other; only the intervention of Athena prevented that Achilles killed Agamemnon. Nestor, the king of Pilo, tried in vain to appease the discord. Agamemnon had already announced that, returned Chryseis, it would have taken away from Achilles the slave Briseis; Achilles retired himself in his tent. He would have left without not intervening, that Hector and the Trojans massacred the Greeks.
Agamemnon submited to Ulisses the assignment to bring Chryseis to her father and sent two heralds to Achilles' tent to take Briseis. Achilles ordered to his friend Patroclo to deliver the dear slave and then he cried, wrathful and desolate. From the sea, Tetis, Achilles' mother, sprang to comfort him, she promised him that she would have asked revenge to Zeus for him.
Meanwhile Chryse, to which Ulisses had returned Chryseis, prayed Apollo to make stopping the pestilence. After having done sacrifices to the gods and after an abundant banquet, Ulisses left again for the camp, from which Achilles would have held far himself obstinately.