Revenge and avarice make for an explosive cocktail when the obsessions of two people overlap. Nina is fanatical about her revenge for the death of her cousin. Sam is driven by legends of buried treasure. When Sam's lover Rachel, a journalist investigating International map theft, is kidnapped, he discovers the reasons are more to do with his past as an ex policeman than Rachel's research. Although Sam's actions secure Rachel's release his recklessness leads him to an uninhabited island off the north west coast of Scotland and the ruined Castle Tioram. But the castle is more than a ruin - its subterranean caverns are the hub of a criminal operation masterminded by a renegade MI5 agent involved in drugs and gun running. Only when the avenger strikes does Sam realise he has been lured into a web of deceit with the sole purpose of payback time for his involvement in the death of a serial killer.