Handsome, considerate high school jock Kyle Harding is the only taste the Wheaton sisters share. Tall, fashionable, popular airhead Alexia is dating him, but fails to truly appreciate him, let alone contemplate a serious relationship. Her nerdy kid sister, Hayley, hates the waste and expresses her envy by thoughtlessly wishing on a shooting star to be Alexia. To their astonishment, that happens the next morning. Forced to live each other's lives, but unable to do it well by the other's standards, they soon hate each other even more and deliberately screw up. Gradually, realizing they would both lose out, they learn to appreciate each other's values and reconsider their own. They realize they would only both lose out, learn to appreciate the other's values, and reconsider their own...and resolve the matters of the utterly confused Kyle and their new neighbor, Simon, whose no-longer-secret crush on Hayley was confounded by Alexia.