Terry Pratchett 
Guards! Guards!: The Play [EPUB ebook] 

Terry Pratchett’s infamous city of Ankh-Morpork is under threat from a 60-foot fire-breathing dragon, summoned by a secret society of malcontented tradesmen.Defending Ank-Morpork against this threat is the entire, underpaid, undervalued City Night Watch – a drunken and world-weary Captain, a cowardly and overweight Sergeant, a small opportunistic Corporal of dubious parentage…and their newest recruit, Lance Constable Carrot, who is upright, literal, law-abiding and keen. Aiding them in their fight for truth, justice and the Ankh-Morporkian way are a small swamp dragon and the Librarian of Unseen University (who just happens to be an orang-utan).