Wilbur's niece Vivian comes to visit him and Carol for the summer. it's been a long time since they've seen each other and Wilbur hopes to rekindle the close friendship they had when Vivian was little. but when Wilbur finds out about an accident that changed the way Viv looks at horses, it's up to him and Mister Ed to help the young girl rediscover her love of horses.