If you are asking about the plot of Romeo and Juliet, it can be thoroughly explained in the eNotes' study guide. But it has a few simple components. The first component is that the plot revolves around a longstanding feud between two noble families of Verona, the Montagues and the Capulets. The second component is that each family has a son and a daughter respectively who meet one night when Romeo Montague decides to join his friends Benvolio and Mercutio in crashing a ball the Capulets are hosting. Thirdly, Romeo Montague and Juliet Capulet fall in love at first sight and arrange to marry the next day in secret. Fourthly, Friar Laurence agrees to marry the couple because he feels the marriage will give the two families a reason to unite, thereby ending the feud, as we see in his lines:
In one respect I'll thy assistant be;
For this alliance may so happy prove
To turn your households' rancour to pure love. (II.iii.93-95)
The fifth component to the plot is that, sadly, Juliet's cousin Tybalt recognizes Romeo at the ball and, feeling insulted by Romeo's presence, challenges Romeo to a duel. When Romeo refuses to fight Tybalt, Mercutio challenges Tybalt and is killed. Then Romeo feels compelled to revenge Mercutio's death and kills Tybalt, leading to Romeo's banishment from Verona. Sixthly, Count Paris wants to marry Juliet, and Lord Capulet agrees to the match as he believes a marriage will distract Juliet from what Lord Capulet perceives to be her grief over Tybalt's death. Lord Capulet forcing Juliet to marry Paris leads Friar Laurence and Juliet to form a plan to fake her death through a potion in order to prevent her from committing polygamy by marrying two men at once. Finally, Romeo does not hear in time that Juliet's death is fake, and believing her to be truly dead, goes to her tomb to commit suicide via taking poison and die by her side. When Juliet awakes in the Capulet tomb to find Romeo dead, she draws his dagger and kills herself as well, leading to the final tragedy of the play. However, on a happy note, Romeo's and Juliet's deaths make Lords Capulet and Montague finally see the error of their ways and make peace with each other, as we see when Capulet says to Montague, "O brother Montague, give me thy hand" (V.iii.307).
However, the play is about so much more than the plot. It discusses many different and intriguing themes, such as longstanding grudges; the consequences of intense, violent, passionate emotions vs. using the rational mind; and even the differences between infatuation and real love. All of which are also worth investigating and understanding.