When international negotiator Sam Jardine joins Napier & Beckett, the pharmaceutical company founded by his ancestor two centuries ago, he believes he's found his place in the world. But after a series of brutal murders, Sam discovers his employer is hiding a deadly secret.

Napier & Beckett has resurrected Berserker, a battlefield drug that turns soldiers into fearless killing machines. The drug works, but it carries a fatal flaw: its users are fated to be violent outcasts known as ‘sleepwalkers’. And Sam's own family is inextricably linked to the drug's dark history. 

Now, Sam must draw on his skills and unshakable sense of justice to complete his ancestor’s quest to destroy Berserker or watch those he loves inherit the devastating Sleepwalker Legacy.