First off, this book is tiny small. Only disappointment is in length 22pages not giving time to really feel it. Picked up because it‘s challenged in my library.
So, it is a beautifully colored book about a boy, Julian, who lives mermaids. He aspires it so much he strips and uses his abuelas decorations to turn himself into one. No direct mention of trans, but a boy trying to be someone whom society generally says he can‘t be. Let boys be creative