The Smurfs set out to help out an elderly human couple.

One night when the moon was blue, in the land of the Smurfs, a stork left a strange little basket containing a baby Smurf on the doorstep of a house.

The Smurfs come to the rescue of two children and their grandfather when an evil mysterious stranger shows up and causes their sleigh to turn over, forcing them to seek help and inadvertently bring Gargamel in on the action.

The evil wizard Gargamel--who hates spring because it makes the Smurfs happy, and he hates happy--devises a scheme to put Mother Nature to sleep.

Jokey Smurf's birthday is on Halloween and so is Gargamel's. Papa Smurf sends Lazy Smurf out to gather red leaves for Jokey's birthday party. Of course, Lazy falls asleep in the woods and Mother Nature turns him red while she is coloring leaves.