Determined to push the investigation forward, PS David Budd targets enemies of home secretary Julia Montague. As he delves into Julia's political manoeuvring before the attack, David’s theories about a conspiracy at the heart of government look increasingly plausible.

Principal Protection Officer David Budd has made a major breakthrough in the investigation into the attack on the home secretary, but his enquiries have put him in mortal danger. With the clock ticking and no-one left who believes him, David attempts to prove his innocence. But the evidence against him begins to stack up.