In this romantic comedy, Shakespeare is portrayed as a young, struggling playwright, plagued by money shortages, problems with women, and writer's block. Some of the characters and their lines are references to lines and characters in real Shakespeare plays -- implying that these inspire the film's Shakespeare later in life.
Warning: Wikipedia contains spoilers
At a fake audition of a play that he has not yet written a word of, "Romeo and Ethel, the Sea Pirate's Daughter", he admires the talent of a new actor, Thomas Kent, who promptly runs away. Shakespeare meets Viola de Lesseps (played by Gwyneth Paltrow), who lives in the same house as Kent, and promptly falls in love with her, which inspires him to begin writing his play again. By the time Will realizes that Viola and Thomas are the same person, she is promised in marriage to a lord approved of by Queen Elizabeth herself (portrayed by Judi Dench). But the couple find themselves unable to avoid a clandestine affair and even risk the wrath of the law against women being on stage by having Viola play "Juliet" in Shakespeare's play, by now renamed Romeo and Juliet. At the conclusion of the play, the Queen applauds the abilities of both writer and "actor," but orders that Viola marry the lord, who is going to move to America.
It should be noted that the movie is entirely fictional, and indeed often inconsistent with the historical record (for instance, the colonization of North America by the English did not begin until 1620, four years after Shakespeare's death, so Viola could not have emigrated there).
On release, the film was compared with the 1941 novel No Bed for Bacon, which also features Shakespeare writing his plays.