Investigative adventure:
A vampire is (seemingly) killing people. What he really does is poison them with a special flower that makes them seem dead. NOT magic poisons, there are many medical states that do this, just read Edgar Allan Poes The Premature Burial. Then the victims are buried alive, as noone dares disect them!
It's quite horrible actually; just read the aforementioned title (short story).
The vampire does this, because when he was bitten by another vampire, he didn't really die, and was buried alive. He awoke in his grave, which allowed some air to enter because of sloppy digging. He died in his grave, alive--buried alive. Now he wants to exact vengeance on everyone he ever felt wronged by, as the vampire who did this to him is long gone...
Work a bit on this plot, and it may become very cool and frightening/ravenlofty.