When Mary Kate joins a science class focused on climate change, she becomes aware of lots of things she never noticed before: Kids waste tons of food at school without a second thought. Parents leave their cars running in the pick-up lane all the time. People buy lots of clothes they don't really need. Mary Kate and her friends have big plans. And now is the time for the young people to lead and the leaders to follow - or get out of the way. 10+ An inspiring call to all readers to make their voices heard.