Winnie the Pooh, Piglet, Owl, Kanga, Roo, and Rabbit are preparinga suitable winter home for Eeyore, the perennially dejected donkey, but Tigger's continual bouncing interrupts their efforts. Rabbit suggests that Tigger go find others of his kind to bounce with, but Tigger thinks "the most wonderful thing about tiggers is" he's "the only one!" Just in case though, the joyously jouncy feline sets out to see if he can find relatives.
When Piglet comes up missing his Hundred Acre Wood friends use Piglet's own Book of Memories to find him, discovering along the way just how big a role he's played in their lives.
One day, Winnie-the-Pooh and his friends hear a strange noise and find a set of large, circular footprints in the Hundred Acre Wood. The friends believe that there is a strange creature known as a "heffalump" in the woods. Rabbit organizes an expedition to go try to catch it. Roo wants to come along, but the others tell him he is too young and small to go. Despite this, Roo slips out on his own in search of the heffalump. He finds one; a playful young creature named Heffridge Trumpler Brompet Heffalump IV - "Lumpy" for short. Roo is afraid of his captive at first but the two quickly become friends and play.