Children's science series in which Ed and his cactus companion Oucho travel all over the country making inventions from bits of old rubbish that they find in the back of their van. Ed and Oucho are in West Yorkshire trying to build Billy's Spar-Master, a karate practice machine. As if their lack of science know-how weren't bad enough, they are also being chased by a very angry man who has it in for them. Will they manage to make Billy's Spar-Master or will the angry man finally catch up with them?