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.