In Ryker's basement you can meet a turtle called Betty that loves a rat called Rory. She asks you to bring the rat to her.
Rory is near an entrance to the basement. Speak with him and you will learn that he is very hungry. Use this knowledge. Create a path made out of food that leads to Betty. The rat will go straight to the turtle.
If you don't have enough food, you can use Teleportation spell. Using it lowers Rory's and Betty's support for the character that used the spell but this isn't important.
The distance between Rory and the turtle is marked in a certain way. If the couple is together they will be surrounded by a purple cloud.
If you managed to do that then you can speak with Betty and complete the quest.
Reward: 7,725 experience points