Twelve-year-old soccer star Dennis is a little lonely - his mom left a couple years ago, his dad isn't dealing with it well. So when he strikes up a friendship with Lisa, a glamorous fashionista a couple years older, it's the best thing to happen in a long time.
When Lisa suggests she try on come of her clothes, Dennis is a bit torn: he want to try on the beautiful dress and he's curious how it looks and feels - but he's a boy! Lisa prevails, and Dennis is elated. Then, she has an idea: Hey - how about you go to school this way! I'll say you're a foreign-exchange student so you don't have to talk! I'll bet no one notices you aren't a girl!
The kids don't consider the implications of their scheme, and it goes as bad as one would expect. But there's more to the story, and it's not as down-pat as you might anticipate.
One of the most interesting things about this book is that Dennis is young enough he isn't really considering his sexuality - for him, this is more about the clothes. He's maybe got a bit of a crush on Lisa, but that's not really the focus, either, and nobody in the book asks him if he fancies boys or if he wishes he was a girl - it's totally about what you're wearing.
The story moves fast, and the lively illustrations (by the incomparable Quentin Blake) add to the story without turning it into a picture book. This book would be an awesome conversation starter with a younger age-group, and fun to read, too.