While en route to join them, General Aulus Plautius's wife and children are shipwrecked in a storm, and fall into the hands of a dark sect of Druids who now demand the return of their brothers taken prisoner by the Romans.

Centurion Macro and Optio Cato are summoned to General Plautius' tent, and tasked to infiltrate enemy territory and rescue the hostages before they are sacrificed to the Druids' dark gods.

Time is running out, as the Roman army is approaching their location in its continuing campaign against the Durotriges, and the Druids will execute the hostages before letting them be rescued.

After desperate fighting, the General's wife and children are rescued from being burned alive, and Cato manages to kill the Head Druid but is seriously wounded with a sickle.

Earlier in the novel, Macro realizes through his conversations with Boudica that even the "friendly" British tribes, such as the Iceni, are fiercely independent, and might do terrible damage if the Roman occupiers do not treat them with respect.