The genre of the book is horror and adventure, it's not scary but more gory.  A Little Person and a vampire go on an adventure to find the Lake of Souls because Harkat, the Little Person, is having bad dreams.  If he does not find out who he was before he died and turned into a vampire he will die. 

The main characters are Darren Shan, the vampire and Harkat Molds, the Little Person.  They are best friends and stick up for each other.  They are both very brave.  Their creator, Mr. Tiny, gives them clues and tasks to find it.  They face panthers, giant frogs, dragons and many more mysterious animals.  Harkat finds The Lake of Souls and fishes for his past.  That man was Kurda Smahlt.  He was a traitor to the vampires and killed one of Darren's best friends.  Only one can live, the other has to die.

The ending is so unexpected, they find out that the world they were in was the future.  You don't find anything else out and this leaves the story open for the next book.

I would recommend it to any child.  I don't usually like horror but it's very gripping, funny and interesting.  There are quite gory bits which aren't very pleasant and are explained in detail.  It is an excellent book and if you like this one you'll like all the others in the series.