"A boy washing the dishes wonders where the water goes, and the story follows water drops as they travel to through the city sewer system, treatment plant, and back again"--
"A boy watching a garbage truck pick up his trash wonders where it goes, and the story follows two garbage bags as they travel to a transfer station and then to a landfill"--
"A girl tosses her plastic bottle in a recycling bin and the story follows that plastic bottle through the process of recycling until it becomes a new bottle again"--
"A girl tosses her old homework paper into a recycling bin and the story follows that paper through the process of recycling until it becomes usable paper again"--