The Robinsons are just about to lift off from their doomed planet when Penny, having gone outside to fetch her scarf, is confronted by J-5, an alien boy who is the sole survivor of another world's colonizing expedition. J-5 lives in terrible fear of a creature called a "Zaybo," which suddenly appears as a lion and is destroyed by Prof. Robinson with his laser pistol. The Zaybo is actually a physical embodiment of J-5's psyche, meeting his needs for companionship and protection.