500 XP, Slicer
Talk to Jeannine downstairs in the Lifeguard Station to begin this quest. Retrieve her necklace from bungalow #6 in the Silver Bungalows District. Follow the mini-map to the bungalow. You'll find that it's blocked in with a truck. Drive the truck out to get in the room. The necklace is in the back on a shelf.
There is also an opportunity to start the Bloody Valentine side quest.
Bring it back to her at the Lifeguard tower to claim your reward.