 Buckaroo Banzai is a rock-star/brain-surgeon / comic-book-hero/samurai/ etc who along with his group, the Hong Kong Cavaliers, must stop evil creatures from the 8th dimension (all named John) who are trying to conquer our dimension. He is helped by Penny Pretty, who is a dead ringer for his late wife, and some good extra-dimensional beings who look and talk like they are from Jamaica.