超级大海龟 “Great ATuin” 的背上，站着四头大象；大象的背上，驮着一个奇异的圆形世界－－人们称之为“ 碟形世界” （荒诞世界／异想世界）。虽然那里的文化看起来很像人类的中世纪，但他们和我们有着本质的不同。海龟，大象，还有碟形世界里的人们，他们一起在广漠的太空中遨游。 　　Ankh-Morpork城，“看不见的巫师学院”，学生Rince…

A former soldier is brought out of retirement and put in charge of Royal security but he turns out to be the worst possible appointment as he is totally out of his depth.