When a mysterious package lands on Louisa Hancock's doorstep, the Philadelphia museum curator can hardly anticipate the nightmare that's about to envelop her. The package is addressed to her father--an expert in Viking culture--and inside is a ninth-century sword, a chilling thank-you note, and photos of two dead bodies in a tableau evoking a Nordic funeral. The gruesome images match a recent crime scene. But before the police can investigate the killer's connection to Louisa's father, Ward Hancock vanishes. Sports bar owner Conor Sullivan wants nothing more than to spend his life with Louisa. Devoted and protective, he refuses to leave her side after her father's disappearance. When a troubled young boxer he's been coaching is suspected of the murders, Conor is pulled in even deeper. Desperate, Louisa and Conor take it upon themselves to find her father, but soon another ritualistic slaying makes it clear there's a Viking-obsessed serial killer on the loose. And he has a new target: Louisa.