Comedy based on two plays by Menander, The Eunuch and The Flatterer.
Phaedria, a penniless young man who has previously been rebuffed by his lover, the courtesan Thais, is surprised to find that she now requests his presence at her house. In an effort to please her he has secured a eunuch to be her servant. Confronted by Phaedria, Thais explains that Phaedria's rival Thraso, a well-to-do soldier, has given her a slave girl. Thais believes her to be her adopted sister Pamphila, who was sold into slavery by her uncle. However, Thraso, upon hearing of Phaedria's friendship with Thais, refuses to give the girl up until Thais agrees not to see Phaedria again. Wishing to restore Pamphila to her family, she entreat's Phaedria to allow her two days alone to humour the jealous Thraso. To cooperate, Phaedria retreats to the country.
Meanwhile, his younger brother Chaerea has seen Pamphila and fallen in love with her. Encouraged by Phaedria's servant, Chaerea poses as the eunuch whom Phaedria has promised to Thais, enters the house where the slave girl lives, and rapes her while Thais is dining with Thraso. To determine Pamphila's true identity, Thais summons Chremes, a citizen whose sister is said to have been kidnaped. Thraso, seeing Chremes, accuses him of being Thais's lover and out of revenge decides to take back Pamphila, now at Thais's house. However, Chremes proves that Pamphila is his freeborn sister.
When Phaedria returns, he learns of Chaerea's impersonation. About to be punished by Chremes for his violation of Pamphila, Chaerea vows his true love for Pamphila, and the two are betrothed. Thraso agrees to remain the lover of Thais on whatever terms she wishes, but she will love only Phaedria. Phaedria, deciding that Thraso may help him support Thais, happily agrees to share his love.