Unlike his brother Zim, Luna is a little red-haired, hot-tempered cat. While his feline furry friend scurries and climbs around the house, Luna grrrrs and growls, being his grumpy self. With their piercing eyes, pudgy bellies, and little pads on their feet, even the best of us can't resist cats! But even though they make us laugh, cats aren't always in a good mood. Will Luna's human and his brother be able to cheer him up?