To the consternation of the patrician Lord Vetinari a new invention has arrived in Ankh-Morpork - a great clanging monster of a machine. It's soon drawing astonished crowds some of whom caught the zeitgeist early and arrive armed with notepads and very sensible rainwear. Moist von Lipwig is not a man who enjoys hard work. However he does enjoy being alive which makes a new job offer from Vetinari hard to refuse… Steam is rising over the Discworld driven by Mister Simnel the man wi' t'flat cap and sliding rule. Moist will have to grapple with gallons of grease goblins a fat controller and some very angry dwarfs if he's going to stop it all going off the rails…