When Thomas Pitt is tasked with playing bodyguard to Sofia Delacruz, a young and controversial British preacher who has been living in Spain and has returned to England on a mysterious errand, he thinks it's a waste of Special Branch's time and resources. But when kidnappers manage to reach Sofia murdering two of her companions in the process. Pitt learns that the message the lovely evangelist was meant to deliver was far more urgent than he knew. With his career on the line, he races to unravel the truth behind Sofia's disappearance, enlisting the help of his beloved wife Charlotte and his old friend Victor Narraway. And he soon realizes that if he cannot find Sofia before it's too late, the consequences could destroy not only his reputation, but the British empire itself.