Awakened by a rumbling that could only be made by the much-feared Heffalump the Hundred Acre Wood crew sets forth to catch the dreaded creature. Disregarded as too young to partake in such a dangerous expedition Roo opts to search on his own -- with far greater success than his friends. But in meeting a young playful Heffalump named Lumpy Roo quickly discovers that Heffalumps are nothing like what he's been told and that the creature is equally afraid of Roo's silly pals. Roo and