The play begins with Sir John Bevil coaxing his son, Bevil Jr. to marry Lucinda, the daughter of Mr Sealand, a very wealthy man. Sir Bevil wants Bevil Jr. to settle down, marry and have children soon. However, Bevil Jr. is in love with Indiana, a poor orphan girl and his friend, Myrtle is in love with Lucinda, who he is to marry. Indiana was raised by her aunt, Isabella who is Mr Sealand's sister. Indiana is in reality the daughter of Mr Sealand from his first wife but nobody is aware of this.
Mrs Sealand is intent on Lucinda marrying her vain cousin, Cimberton because he is more wealthier than the Bevils. Mr Sealand on the other hand wants Lucinda to marry Bevil Jr. Cimberton, because of his vast inheritance and fortune cannot marry until he procures his Uncle Geoffrey's or his council of lawyers' consent. When Myrtle and Bevil Jr. hear of this they devise a plan to delay the wedding. They decide to diguise Myrtle and Bevil Jr.'s servant, Tom as Sir Geoffrey's lawyers. When the two arrive at Mr Sealands home they manage to convince both Cimberton and Mrs Sealand that Cimberton's marriage cannot happen without the physical presence of Sir Geoffrey. Mr Sealand and Sir John, in the meantime, discuss Bevil Jr.'s morals when they hear that he frequently visits a woman of a lower class. To judge Bevil Jr.'s conduct for himself, Mr Sealand decides to visit the young woman that Bevil Jr. visits.
On the next day, Lucinda's maid, Philis rushes to Bevil Jr.'s chambers and informs him that Sir Geoffrey is expected to come to town very soon. Bevil Jr. urges Myrtle to disguise as Sir Geoffrey so that the marriage proceedings may be further delayed. Mrs Sealand is in a hurry to marry Lucinda to Cimberton in Mr Sealand's absence and she begins the marriage proceedings.
Isabella recognizes Mr Sealand when he arrives at her lodgings to meet Indiana, however, Mr Sealand doesn't recognize his sister. Mr Sealand talks to Indiana and she tells him about her life, she drops a bracelet when she cries and Mr Sealand immediately recognizes the bracelet as the one that he had given his first wife. He is happy to be reunited with his daughter and sister and insists that Indiana must marry Bevil Jr., the man she loves. Indiana goes to fid Bevil Jr. and returns with Bevil Jr., Sir John Bevil, Mrs Sealand, Cimberton, Lucinda and Myrtle disguised as Sir Geoffrey.
In the final scene of the play, Mr Sealand says that he would rather have Myrtle marry his daughter Lucinda than Cimberton and now Cimberton would not marry her regardless because her dowry has been halved by the discovery of her new sister, Indiana. Cimberton leaves and the young lovers are finally united.
At the end, Sir John Bevil moralises that the happiness of the young can be derived from providence, honesty and good virtue.