Greedy Greg learns how to save energy - then tries to profit from it. When his “Greedy” rebrand backfires, he’s forced to go green for real.

Stefon travels back to the 1840s to meet Esther Howland, discovering how handmade valentines—and a lot of care—turned simple cards into a lasting tradition.

After polluted London air makes them ill, Naeco and Ria uncover acid rain and microplastics—then race back to help clear the city’s skies.