Egeon, a merchant of Syracuse, is arrested in Ephesus because of hostilities between the two cities and, unable to pay the local ransom, is condemned to death. He tells the duke, Solinus, his sad tale: years earlier he and his wife had been shipwrecked with their infant sons, identical twins, and a pair of infant servants, also identical twins. The parents, each with a son and a servant, were rescued but then permanently separated. Antipholus of Syracuse, the son raised by Egeon, has for five years been seeking his mother and brother, while Egeon in turn has been seeking his missing son. Egeon's story wins from Solinus a day's respite to raise the ransom money.

Meanwhile, Antipholus of Syracuse (with his servant, Dromio) has arrived in Ephesus, not knowing that his brother Antipholus of Ephesus (with his own servant, also named Dromio) is already there. A series of misidentifications ensue. Antipholus of Syracuse is entertained by his brother's wife and woos her sister; he receives a gold chain meant for his brother and is chased by a goldsmith for nonpayment. He and his servant hide in a priory, where they observe Egeon on his way to execution and recognize the priory's abbess as their mother, Emilia. The play ends happily with Egeon's ransom paid, true identities revealed, and the family reunited.

For a discussion of this play within the context of Shakespeare's entire corpus, see William Shakespeare: Shakespeare's plays and poems (Shakespeare, William).