A merchant from Syracuse, named Egeon, is arrested as soon as he sets foot in Ephesus, a town where Syracusans are absolutely forbidden, due to trade disputes between the two cities. Egeon is sentenced to death that very day unless he can pay a heavy ransom. The Duke asks the traveler to explain the cause for his blatent trespass. Egeon recounts that twenty-three years before, he and his family were shipwrecked, separating him from his wife, and their infant identical twin sons from one other.
Upon turning 18, Antipholus of Syracuse left his father and their home and went in search of his missing brother, bringing with him his servant, Dromio of Syracuse, who also lost his identical twin brother in that same shipwreck. For five years, Egeon has been searching the world over for word of either of his sons, a journey that brought him at last—albeit illegally—to Ephesus. Egeon says that he is ready for his woes to end. But the Duke grants the stranger the day to gather a ransom of 1,000 marks. Only if he can gather the money will Egeon escape execution.
On that very same day, Antipholus of Syracuse and his slave Dromio also arrive in Ephesus, where they are warned by a merchant to keep their Syracusan origins secret, lest they end up like the merchant apprehended earlier that day. Antipholus of Syracuse sends Dromio with his 1,000 marks back to their inn for safekeeping. Left alone, Antipholus speaks about his long search for his missing twin, but is interrupted by Dromio of Ephesus. As it happens, the other twins-presumably lost at sea and also named Antipholus and Dromio—already reside here in Ephesus! Mistaking Antipholus of Syracuse for his own master, Antipholus of Ephesus, Dromio pleads with him to return home to his wife. The traveler regards the person he takes for his servant warily, and asks him why he is not guarding the money. Dromio of Ephesus denies knowledge of any money and Antipholus of Syracuse strikes out at him as Dromio takes to his heels. Antipholus remarks on the reputation of Ephesus as a town filled with magic and sorcery, then rushes back to the inn to secure his money.
Adriana, wife of Antipholus of Ephesus, complains bitterly to her sister Luciana about her husband's absence from home. The two sisters argue over the proper behavior of a husband and wife: Luciana (the younger of the two and still unmarried...) urges wifely obedience, while Adriana asserts that she should maintain her voice and independence in matrimony. Dromio of Ephesus returns home to tell his mistress of the beating he has just received at her husband's hand, but Adriana sends him right back out again to bring his master home for lunch, and Dromio reluctantly leaves. Adriana mentions her husband's affinity for other women's company, but Luciana dismisses her sister's concerns as unfounded jealousy.
Antipholus of Syracuse comes upon Dromio of Syracuse and scolds him for "his" earlier misbehavior. Dromio proclaims his innocence, and the frustrated Antipholus beats him. Adriana and Luciana come upon the two in the street, and Adriana scolds the man she takes for her husband for all his gallivanting. The Syracusans are taken aback and claim no knowledge of the women or their accusations. But intrigued by their insistence, and attributing it the town's reputation for sorcery, Antipholus allows the sisters to take them back to Adriana's home.
Antipholus of Ephesus invites his friends, the goldsmith Angelo and the merchant Balthasar, to dinner at his house. But when they get there, Dromio of Syracuse—serving as the bouncer under orders from Adriana—refuses them entry. Antipholus is furious and causes such a scene that the kitchen-maid Nell and Adriana inquire about what all the hubbub is below. Neither woman believes Antipholus of Ephesus's claims, and he is turned away from his own home. Enraged, he yells out that he will visit the Courtesan, and decides that after Angelo delivers the gold chain he meant to give Adriana as a gift, he will now give it to the Courtesan instead.
Antipholus of Syracuse tells Luciana that he neither recognizes Adriana as his wife, nor cares for her, and professes instead his love for Luciana. She is shocked that the man she believes to be her brother-in-law would say such things to her. She runs off, leaving Antipholus there in the house, more baffled than ever.
Dromio of Syracuse, finding his master there, is in a tailspin himself after his encounter with the gargantuan kitchen-maid Nell, who is claiming him as hers. Antipholus, now fed up with the "magical" nature of the town, sends Dromio to collect their things and prepare for their departure post haste. He explains away his attraction to Luciana as supernatural. Angelo comes along and gives him the gold chain that was intended, of course, for Antipholus of Ephesus. Antipholus of Syracuse protests that the chain is not his, but accepts the expensive jewelry in the end.
Accompanied by a collections officer, a merchant is looking for the goldsmith to demand that he immediately repay his debt to him. Angelo says that he can repay the merchant as soon as he receives the money Antipholus of Ephesus owes him for the gold chain. But when Antipholus of Ephesus comes in with his Dromio, he claims to have not yet received the chain from Angelo, and sends Dromio off to buy a rope to use on his wife for barring him from their home the night before. Though Antipholus objects vehemently, insisting that he will pay the goldsmith just as soon as he receives the chain, he is arrested. When Dromio of Syracuse returns looking for his master so they can escape the town, Antipholus of Ephesus, seeing Dromio without the rope, orders him to find Adriana immediately to bail him out of jail.
Adriana and Luciana discuss Antipholus of Ephesus's infidelity as Dromio of Syracuse returns to the house to ask for money to bail out the man he assumes, of course, to be his master, now in custody of the law. The women take him for Dromio of Ephesus and send him back with the money.
On his way to the jail, Dromio of Syracuse runs into his master and tries to give him the money. Antipholus knows nothing about it and again blames the situation on the enchanted Ephesus. The Courtesan sees them in the street and asks about the gold chain that Antipholus is now sporting around his neck. Hadn't he promised it to her? When he refuses to give it to her, she tells him to return a ring she once gave him. The men think that she is a demon and run away. The Courtesan goes to tell Adriana that her husband is utterly mad.
Dromio of Ephesus encounters his master in the officer's custody. Antipholus sees that he has the rope now, but no bail money. He uses the rope on Dromio, who complains bitterly about his constant abuse. Adriana, her sister, and the Courtesan arrive with Dr. Pinch, a schoolmaster with skills he claims can cure madness. Beside himself, Antipholus strikes out at Adriana, prompting him and Dromio to be restrained with the rope and taken to Adriana's house for Pinch's treatment. When Antipholus and Dromio of Syracuse return, everyone flees in fright, thinking the men are the escaped prisoners seeking revenge.
The goldsmith Angelo converses with a merchant about Antipholus's odd behavior. When he sees Antipholus sporting the gold chain around his neck that he denied ever receiving, Angelo accuses him of theft. Antipholus and the merchant draw swords, but Adriana, Luciana, and the Courtesan step in to stop the fight. The women ask for help in recapturing the pair of men they think have escaped. Antipholus and Dromio run away, and take refuge in a priory. Adriana follows them and demands their extradition from the Abbess. The Abbess refuses. The Duke appears and Adriana appeals to him. The Duke has with him the unfortunate Egeon who, without the ransom, is slated for immediate execution. Antipholus and Dromio of Ephesus, having escaped the clutches of Pinch, arrive on the scene. Antipholus appeals to the Duke to prevent his wrongful incarceration. Everyone is enraged at someone, charging each other with various infractions. The Duke is overwhelmed by the confusion and sends for the Abbess. Seeing Antipholus of Ephesus, whom he takes for his twin, Egeon asks him for the ransom money to save his live; Antipholus, seeing no more than a deranged old man, refuses him. The Abbess appears with Antipholus and Dromio of Syracuse, and the crowd is stunned by the realization that these four men are two sets of identical twins, whose identities are finally clarified. The brothers are reunited, and the Abbess—who happens to be Emilia, Egeon's wife—joyously recognizes her reunited sons, their servants, and her long-lost husband.
– Contributed by the CST Education Department