The Princess Diaries Sixsational by Meg Cabot

How can Mia bear it? Michael, her one true love, has gone away to college, leaving her to face a new school year all alone (well, nearly). With a potential eco-disaster in Genovia, a new English teacher who can't stand her, and a totally transformed Boris to get used to, life for the world's most reluctant royal is looking like it can't get much worse. Until Grandmere and Lilly step in - with a plan to save Genovia and Albert Einstein High. A plan that involves Grandmere showing up at school in her fur cape and tiara!