King and Kayla are going to a sleepover at Thor and Jillian's house. King LOVES sleepovers. They're his favorite thing! And he particularly likes Jillian's basement, because animals are allowed on the furniture. But Jillian and Thor are afraid to go downstairs because there's big, dark blob that goes "Whoooooo!" and chases her around the basement.

Kayla's not worried; she wants to know what's happening downstairs. With her intrepid co-detective, she investigates the weird sights and sounds and solves the mystery--but not before an encounter with Cat with No Name and a run-in with a skunk.