Nocturnal (Quest)

Nocturnal speaks for a time about her Eye of Nocturnal, then informs the Hero that it has been stolen. She tasks them to find out where the thieves have hidden it, and return it. In passing she makes reference to a pair of Argonians, Weebam-Na and Bejeen, in the nearby town.

Walkthrough
After getting permission from one of the followers of the Daedra, approach the shrine and talk to Nocturnal. She talks about her Eye of Nocturnal that has been stolen and mentions possible thiefs in Leyawiin.

Leyawiin
Head to the town of Leyawiin, Ask around about the thieves, and they should get a tip to investigate Weebam-Na's house, which is in the middle of the city, across the street from the house for sale. Asking Weebam-Na and Bejeen about the Eye causes them to act in suspicious manner.

After talking to them, Bejeen will ask Weebam about the Eye, but he will cut her off for fear of someone overhearing them because they are not alone. The journal will update that one should try to listen in without letting your presence be known; leave the house and re-enter, keeping out of sight. Using an invisible spell or clothing will help in being undetected. They'll overhear them converse about the Eye, which is hidden in Tidewater Cave along the coast south/south-east of Leyawiin.

Tidewater Cave
Head to Tidewater Cave and enter. Inside is an assortment of Kalperklan Trolls and animals appropriate for their level, deal with them accordingly. From the entrance, take all left turns.

The Eye is submerged in a small pool of water at the end of the tunnel, next to a chest. Upon retrieving the Eye, return it to the Shrine of Nocturnal for the reward, the Skeleton Key and the Skeleton Key ability (Fortify Security 40 pts on Self, constant effect).

Trivia

 * There's a Nirnroot south of the door