Damian Crockett lives with his parents and younger sister, Bianca. They dote on Bianca, while despairing of their moody teenaged son. During a family outing Damian meets two aliens called Plingklopt and Plongklopt. Their spaceship is powered by laughter, so Damian asks a group of comedians to go back to Kloptronia with them telling jokes, in exchange for the gold the aliens can create from raw energy. The aliens' little brother, Plug, has been accidentally left behind. With his neighbour, eleven year old Cressida Parker's help, Damian helps Plug to contact them and they arrange to meet in the local supermarket car park at midnight. It should have been simple but things do not go according to plan.