Gappy and the Thieves (Book Four of the Young Vampire Adventures)

Gappy invites three friends to keep him company at a bed and breakfast while his parents are attending a vampire conference. The excitement soon begins with the discovery of a secret passage under the house. Then Gappy bumps into an old enemy, and strange lights appear in a nearby cemetery in the middle of the night. When the friends investigate, Gappy finds himself drawn to a particular monument and the large stone coffin that sits in its center. With the help of some new vampire powers, he explores further, but a midnight adventure quickly turns dangerous when he is trapped underground. Why do people visit the stone coffin in the middle of the night, and what are Gappy's enemies plotting now?