Any light left is the second quest given to the player from Edward. He is worried about the head you found in the Age o Nosferatu quest and requests the player check on the welfare of the probable victim at the nearby lighthouse.
To get to the lighthouse, head back outside the town hall and head dirextly straight along the railway tracks. The lighthouse will be a little way on the left.
Head into the basememt and either avoid or kill the Nosferatu vampires lurking. They are quite quick so fast firing weapons and bullets are reccomended.
Head into the basement of the small house first and find the head mounted on a spike with blood again. Once you have checked that out, head to the top of the lighthouse to find another one.
Once you have seen both, you will trogger a message saying you notice a bite mark on your arm that you must have sustained while fighting the Nosferatu. Head back to Edward to complete the quest.