What is a summary of Cirque du Freak Hunters of the Dusk?

In "Cirque du Freak: Hunters of the Dusk," Darren Shan discovers the Vampaneze have killed his close friend and fellow half-vampire, Gavner Purl. He joins forces with his vampire mentor Mr. Crepsley and the vampire princes to hunt down the Vampaneze leader, Steve Leopard. The group faces intense battles and moral dilemmas as they seek to defeat the Vampaneze and protect humanity.