This is a solid, cheerful picture book that does exactly what it sets out to do: turn environmental responsibility into a superhero mission that preschoolers can actually tackle. Manny and Gertie are likable, the message is clear without being heavy-handed, and the imaginative play angle makes civic engagement feel fun instead of like homework.

It's not going to blow your mind with originality—the 'kids as superheroes' trope is well-worn—but it's executed well. The illustrations are engaging, the friendship between Manny and Gertie feels genuine, and the book gives little kids a concrete action (pick up trash) that makes them feel powerful.

If you've got a preschooler who's into capes and wants to save the world, this is a great pick. Just know it's a one-note story that won't have much replay value once the novelty wears off.