Potidaea revolts and an unofficial Corinthian force goes out to help.

Potidaea is laid under siege by Athens, with Phormio in command.

Alcibiades, well-born and wealthy, had been only a small boy when his father—who was in command of the Athenian army—was killed in 447 or 446 BCE, at Coronea in Boeotia, and his guardian, Pericles, a distant relation, has been too preoccupied with political leadership to provide the guidance and affection that the boy needed.

Alcibiades has grown up to be a strikingly handsome and keen-witted teenager, but he is extravagant, irresponsible, and self-centered as well.

He is, however, impressed by the moral strength and the keen mind of the philosopher Socrates, who, in turn, is strongly attracted by Alcibiades' beauty and intellectual promise.

They serve together at Potidaea, where Socrates defends Alcibiades when the latter is wounded.