The Suicide Motor Club by Christopher Buehlman

Set against the backdrop of the 1960s, this gripping horror novel follows the harrowing journey of a woman named Judith Lamb, who is left devastated after a vicious vampire biker gang murders her son and leaves her for dead. As she grapples with her grief and the supernatural forces that have upended her life, Judith becomes entangled in a dangerous quest for vengeance. Her path leads her to a secretive group of vampire hunters, and together, they embark on a relentless pursuit to destroy the bloodthirsty gang, confronting their own fears and the darkness within themselves along the way.