Charlie Ashanti, the hero of Lionboy, speaks cat, the language of all cats wild and domestic alike. His unusual talent helps him on his quest to find his kidnapped parents who have discovered a cure for asthma. The local cats of his home town (a futuristic London) start him on his search to solve the mystery of his missing parents, which leads him across the channel on board a circus ship bound for Paris. It is on this wonderful vessel that Charlie establishes a close relationship with the homesick circus lions who become his accomplices. But Charlie is in danger, for close behind him on his trail, is a crony of the mysterious group who have kidnapped his parents. They want Charlie too.