With his beloved Watch crumbling around him and war-drums sounding, Commander Sam Vimes must unravel every clue, outwit every assassin and brave any darkness to find the solution. And darkness is following him. At six oclock every day, without fail, with no excuses, he must go home to read "Wheres My Cow?" to his little boy. Koom Valley - that was where the trolls ambushed the dwarfs, or the dwarfs ambushed the trolls. It was far away. It was a long time ago. But if he doesnt solve the murder of just one dwarf, Commander Sam Vimes of Ankh-Morpork City Watch is going to see it fought again, right outside his office. With his beloved Watch crumbling around him and war-drums sounding, he must unravel every clue, outwit every assassin and brave any darkness to find the solution. And darkness is following him. Oh...and at six oclock every day, without fail, with no excuses, he must go home to read "Wheres My Cow?", with all the right farmyard noises, to his little boy. There are some things you have to do.