Hegio is a wealthy Aetolian who many years before lost a son, Tyndarus, when a runaway slave named Stalagmus carried the boy off at the age of four years. Later, during a war with Elis, his other son, Philopolemus, is captured and made a slave by the Elians. In an effort to rescue Philopolemus, Hegio buys up prisoners of war captured by the Aetolian army, hoping to find a wealthy young Elian whom he could exchange for his own son. He spends a great deal of money without finding a suitable prisoner. Mourning his son’s loss with him is a parasite, Ergasilus, a favorite of Hegio’s son and the recipient of many free meals.

One day, entirely by accident, Hegio buys a pair of prisoners of whom one, unbeknownst to him, is the son stolen years before. Tyndarus is now the slave of Philocrates, a wealthy Elian prisoner. Philocrates and Tyndarus change clothing and names, hoping by that ruse to get Philocrates set free to return to Elis. The ruse works, for Hegio allows Philocrates to return to Elis and arranges for an exchange of his own son for Philocrates’ “master.” Shortly afterward, Hegio, while visiting at his brother’s home, finds a slave there named Aristophontes, who claims to be a friend of Philocrates. To satisfy himself as to the identity of his hostage and to do a kindness to both prisoners, Hegio takes Aristophontes home with him. At Hegio’s home, Aristophontes lays bare the ruse that was played on Hegio. At first, Tyndarus, still posing as Philocrates, tries to complete the plan by claiming that Aristophontes is mad, but Hegio soon becomes aware that Tyndarus is not Philocrates. In his anger, Hegio has Tyndarus, actually his own son but whom his father does not recognize, sent to the stone quarries, with orders that he is to be worked hard for the trick he played on his new owner.

The parasite Ergasilus, meanwhile, is going hungry in the absence of his patron, Philopolemus, although Hegio occasionally gives him a frugal meal. Ergasilus is the victim of a move on the part of the wealthy Aetolians to pay no attention to parasites, thus forcing those unwelcome individuals to earn an honest living in some way or other.

Elian Philocrates is an honest man who loves his slave Tyndarus, for the two were companions since childhood. Upon his return to Elis, therefore, he arranges for the exchange of Philopolemus in return for his own freedom. He also decides to go with Philopolemus to Aetolia to regain his slave Tyndarus. He promises, through the false Philocrates (Tyndarus), to pay a sum of money as bail for Tyndarus’s return.

The first person to see Philocrates and Philopolemus is the parasite Ergasilus. Realizing that the news is money in his wallet and food in his stomach, he rushes off to tell Hegio the tidings. Overjoyed, Hegio promises to give Ergasilus his board for the rest of his life and, for one meal, to give Ergasilus free rein in the kitchens. While Ergasilus rushes to have a feast prepared, Hegio goes to the harbor to meet Philopolemus and the former prisoner, Philocrates. Hegio’s joy knows no bounds when he embraces his son.

As soon as he returns to his house, Hegio sends for Tyndarus, whom he still does not recognize, and has him released to his master Philocrates, without demanding the payment he initially set for Tyndarus’s freedom. While they are waiting for Tyndarus, Hegio questions Stalagmus, his former slave, who was recaptured at Elis and returned by Philocrates. Hegio hopes to discover what happened to...