Bertha is a big green engineering machine, a marvellous mechanical production engine with a big toothy face who could be programmed to manufacture just about anything you wanted. She was housed at the busy Spottiswood Factory, owned by Mr Willmake. Her Chief Designer was Mr Sprott. Sprott was ably assisted by young Tracy, who indeed, often sorted out flaws and problems with Mr Sprott's work. Other Spottiswood employees included Mr Duncan the foreman, Ted Turner who was Bertha's operator, young Roy Willing his kenn-but-slow assistant, Nell and Flo who packed and stacked items, Panjid the fork-lift driver, Mrs Tupp the tealady, and Miss McClackerty who was Mr Willmake's secretary.