When a pub landlady is stabbed to death and her little finger cut off, her husband, Roly, is the prime suspect. However, as Nikki, Jack, and emotionally fragile detective, DI Kate Warren, piece together mounting evidence, inconsistencies lead Nikki to believe Roly's innocent. She's desperate to reunite him with his traumatised daughter, Emma, who faces a life in foster care if her father is imprisoned.
Isolated in her quest to prove Roly's innocence, Nikki is defeated when Roly is charged with murder, and about to lose his daughter forever. But when Nikki and Leo unearth several old murder cases where the victims' fingertips were cut off, they begin to suspect Roly is the new target of a serial killer. The spotlight soon falls on ex-cop Alan Lane, who served eight years for killing his wife, Imogen, despite her body never being found, only her severed fingertip.