Five years after
first learning she was a princess, Mia has returned to Genovia to assume the position of queen only to discover that a male heir exists, Lord Nicholas Deveraux, the nephew of the scheming Viscount Mabrey. In order to inherit the throne, Mia must marry within the month, so she enters into an engagement with Andrew Jacoby, Duke of Kenilworth. Unwilling to accept this, Mabrey instructs Nicholas to seduce Mia so the engagement will fail. Nicholas begins to seduce Mia and the two begin to fall in love, something that is witnessed by both Mabrey as well as Mia's grandmother, Queen Clarisse. Nicholas realizes that Mia would make an excellent queen and is more deserving of the throne than himself or his uncle. Aware that this would derail his plans, Mabrey manipulates Nicholas into believing that his father wanted Nicholas to become king. Two days before the wedding, Nicholas convinces Mia to sneak out and join him for a night of fun. The next morning, they awaken to find a man filming them, causing Mia to angrily accuse Nicholas of setting her up and leave. The footage is widely shared, prompting Andrew to realize that there is no romantic spark between him and Mia. The two decide to marry anyway the following day, for the good of Genovia. Just before the wedding, Mia learns that Nicholas was innocent and that the scandal was set up by Mabrey. Knowing that she does not want to enter into a loveless marriage, Mia halts the ceremony and runs out of the church. She is followed by Clarisse, who encourages her to follow her heart, something she never did, costing her Joe, the love of her life. Mia returns to the church and asks the members of Parliament to abolish the law on royal marriages, asking if they would force the significant women in their lives to marry without love. Despite protestations from Mabrey, Parliament unanimously assents. Clarisse proposes to Joe, and they are promptly married. A week later, Mia is preparing for her
coronation when Nicholas arrives. He professed his love on bended knees, and they kiss. The next day, Clarisse steps down, and Mia is crowned "Her Majesty Amelia Mignonette Thermopolis Renaldi, Queen of Genovia.” An
epilogue shows that the Genovian Parliament now allows female members, one of whom is Charlotte (Clarisse's
lady-in-waiting). Queen Mia officially opens a new children's home with Carolina, an orphan she had helped earlier in the film. ==Cast==