Jo Tyrell, head of MI5's D section, faces the toughest test of her career, following a hasty cover-up involving the brutal murder of Sir William Houghton. Just twenty-four hours later, members of a sadistic Dark Web forum are slain similarly. But as the murders continue, public support for the vigilante killers grows, undermining the very rule of law.

As investigations widen, Jo discovers that the killers have a much more sinister aim. This startling revelation exposes several high-ranking government officials in an unholy plot to take absolute control of the internet.

But that is just the beginning of the nightmare… Jo must confront her deepest personal fears to prevent a global catastrophe.