Because of recent enmity, no Syracusan is allowed in Ephesus. A Syracusan merchant Egeon, searching for his wife and twin boys separated and lost at sea, has been found there and arrested. The Duke is sympathetic, so gives him a day to find a way paying his fine before the death penalty has to be carried out.
Antiopholus and servant Dromio of Syracuse (S) arrive in Ephesus, on their travels. They are instantly mistaken by the townsfolk to be Antipholus and servant Dromio of Ephesus (E). Antipholus (E) meets Dromio (S), who denies knowledge of money given to him earlier. Adriana, the wife of Antipholus (E) sends Dromio (E) to find his master. They encounter Antipholus and Dromio (S). Antipholus (S) does not recognize Adriana, and Dromio (S) denies he received instructions from her.
Adriana insists they both accompany her home, and they think they are going mad.
Antipholus (E) meanwhile arrives home with merchant Balthazar and goldsmith Angelo, who is making a gold chain for Adriana. Dromio (S) and kitchen-maid Luce refuse to let them in, much to the annoyance of Dromio (E), so Antipholus (E) goes to a tavern instead. Inside the house, Antipholus (S) has fallen in love with Adriana’s sister Luciana, much to her amazement; and Dromio (S) is awed by a kitchen-maid who claims him as hers.
Antipholus (S) meets Angelo, who gives him the chain, proposing to return later for the money. Angelo, being himself pressed for a debt, later meets Antipholus (E) and asks for his money. When Antipholus (E) denies having had the chain, Angelo has him arrested until he pays the amount. Antipholus (E) sends Dromio (S) to Adriana for the money, which she immediately sends.
Dromio (S) brings the money to Antipholus (S). They meet a Courtezan with whom Antipholus (E) had dined and who asks for the return of a ring Antipholus (E) had taken, but Antipholus (S) of course denies knowledge of it. Dromio (E) meets the arrested Antipholus (S), who asks for the money to obtain his release, but Dromio (E) obviously does not have it. Adriana arrives with Dr Pinch, who tries to conjure the supposed madness out of Antipholus (E). Both he and Dromio (E) resist and they are arrested and taken away. Adriana and the others then immediately meet Antipholus (S) and Dromio (S) with swords drawn, and, confused by their sudden liberty, flee from them.
Angelo meets Antipholus (S), sees the chain, and prepares to fight him. On the arrival of Adriana and the others, Antipholus and Dormio (S) run into a priory for safety. The abbess Aemilia discusses his supposed madness with Adriana, but refuses to let her enter the priory. Adriana decides to complain to the Duke, who is nearby for Egeon’s execution, to get to see her supposed husband. Antipholus (E) and Dromio (E) appear and also complain to the Duke. All parties tell what has happened from their own point of view. Egeon recognises Antipholus (E) as his son, but Antipholus does not know him. Aemilia then brings out Antipholus and Dromio (S), and all is revealed. Egeon recognizes Aemilia as his wife. The Duke forgives Egeon. The two pairs of twins are reunited.