It's probalby to easiest quest on Rookgaard. To complete it, you need to kill a rat, or find a dead one, and take his cropse with you to Saymour NPC. He can be found in liblary (north from temple). Talk to him like that- "hi>rat>yes". You will lose the rat you took, and earn 2gp. This quest can be completed multiple times. The purple circle on the map shows the location where Saymour is.