Garth takes Lassie with him on his visit to Vandenberg Air Force Base, where they meet Jimmy Fredericks, a boy with a weakened leg who has given up believing he will ever walk normally.

Lassie protects a snow goose who has chosen to lay her eggs on the flightline.

Lassie befriends a diabetic poodle named Sparky who stows away on the Looking Glass, where there's no insulin, to be with his owner.

Jimmy finds out that his father's flight may crash and must re-examine his faith.