Koom Valley? That was where the trolls ambushed the dwarfs, or the dwarfs ambushed the trolls. And if he doesn't 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.

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 o'clock every day, without fail, he must go home to read Where's My Cow? with all the right farmyard noises, to his little boy. There are some things you have to do.