In this scene, set in Shylock's house, we are introduced to Jessica, Shylock's daughter. She is speaking with Launcelot, and she expresses her sorrow that he decided to leave his position as her father's servant. "Our house is hell," she says, "and thou a merry devil / Didst rob it of some taste of tediousness." She then gives him a letter to deliver secretly to her lover Lorenzo "who is thy new master's [Bassanio's] guest." After Launcelot leaves, we discover that Jessica is planning to elope with Lorenzo; in addition, she is planning to renounce her father's faith and become a Christian.
This brief scene in Act II provides the final piece of plot exposition. Here, we are introduced to Shylock's daughter, Jessica, and in her first words, we have a clear idea about her relationship with her father, and we receive some justification for her plan to leave the old moneylender's house; she says, "Our house is hell."
Her love letter, to be given to Lorenzo, will figure in the second of the play's love affairs (Gratiano and Nerissa will prove a third in this play). It is important that the audience in this scene and in the next scene be aware of Jessica's elopement with Lorenzo, since it adds very heavy irony to Shylock's multiple warnings to his daughter in Scene 5 to guard his house well.
In this scene, Shylock is cast in the clichéd role of the villain, primarily because of Jessica's remarks, but one should remember that in a romantic comedy, one of the fathers would have to be a villain of sorts; here, it is Shylock. Interestingly, even though Jessica's intention to leave her father's household and rush into her lover's arms seems natural enough, Jessica is aware of her "sin," being her father's child. Finally, though, as part of the romantic plot, all will be well with Jessica, and she will be a part of the general happiness at the play's end.