A pair of royal rangers, Harry and Ron, are chasing a criminal, Blaise Zabini, who ad raped and murdered Ron’s sister, Ginny. They are joined by a young member of the Royal College of Mages, Magus Granger, who is chasing an associate of Zabini’s, Draco Malfoy, due to him committing a different crime.
The chase leads them across the sea, aboard a fast trading ship owned by the Greengrass Trading House, which they help defend from a pirate attack.
In France they catch their quarry, also managing to make a friend there, an officer of a Wing Regiment, Fleur Delacour.
Situation progresses and they uncover damning evidence about how the Malfoys had accumulated much of their wealth during the Black Death, using the epidemic to disguise their murders.
While pursuing the now fleeing Malfoy family, they also uncover evidence that they had been funnelling a lot of funds to a revolutionary conspiracy intending to overthrow the crown, led by a certain Riddle, an unacknowledged bastard son of a nobleman who had been raped by a witch.
During this time, they are also approached by the head of the Greengrass family, who asks them to assist him against air pirates plaguing his air shipping, who had also cost him his older daughter.
A plan is made in cooperation with Fleur to lure the air pirates into an ambush, but they encounter a twist, the leader of the air pirates is none other than Daphne Greengrass herself, as Harry finds out after being captured by her.
He has to manage to lead her into an ambush while resisting the advances of the charismatic and beautiful pirate.