Marcus' stamp collection is of no interest at all to his friends. However, one of the stamps catches their eye. Marcus' 1918 ""Curtiss Jenny Inverted"" stamp, one of the rarest in the world, is worth over a million dollars! The gang smothers Marcus with attention, but it's clear that they're only interested in his stamp for the money. Earl, meanwhile, wants Marcus' stamp for his own stamp collection! Morphing the school into a stamp factory circa 1918, Earl tries to steal the precious postage right after it's made! The kids prevent Earl from stealing the stamp and changing history, but not before learning that greed should never be a motivation for appreciating something.
