It's been several months since the events of The Yellow M, but the evil of Professor Septimus still echoes around London. Important figures of the capital's jet set come together around the questionable values the mad scientist defended. Olrik is forced to resort to opium in order to forget he was guinea pig. As for Mortimer, he too is trying, albeit for more humanist reasons, to revive certain aspects of Septimus's work-to Blake's extreme concern...

Siobhan's blood has brought her victory and the throne, but it contains its own kernel of evil... Time has passed in Eruin Dulea. Siobhan reigns with wisdom and compassion. One day, during a trip with her protector Seamus, she meets Kyle of Klanach, a minor nobleman haunted by his family's dishonour, whose charm doesn't leave her indifferent... Unfortunately, the evil Lady Gerfaut is plotting to place her own son in power. And what better way to do this than a marriage, even if it requires black magic to arrange?

Tasked by the queen to close the 'Septimus Wave' case once and for all, Captain Blake is facing a daunting task, for many questions remain unanswered. Where did the spaceship buried beneath London come from? What became of Lady Rowana and Professor Evangely? Meanwhile, Mortimer is trying to pull Olrik out of the catatonic state the villain has been in since his encounter with the ship's occupant. Has the threat to the nation truly been vanquished?

Jerusalem is in the hands of Sultan Ab'dul Razim, and the Christians have raised an army to take it back, led by Gregoire of Arcos and the Duke of Taranto. Only Gauthier of Flanders and his sister-in-law Syria of Arcos are opposed to an attack they deem premature. But the stench of brimstone covers everything, and in a war fought in the name of God, it is the Qua'dj, a demon, who could decide the fate of the Holy Land -

Will love triumph over evil sorcery ? The Gerfauts' schemes have born fruit. Siobhan drank the blood of Brigga the Witch, and evil has taken hold of her. Once a wise and generous ruler, she has become merciless, and is entirely devoted to Lady Gerfaut's son, whom she soon marries. Her own mother, Lady O'Mara, isn't invited to the wedding, and Seamus, her protector, is powerless to help. The last glimmer of hope lies with Kyle of Klanach and his unwavering love and loyalty...

The first chapter of this epic tale of revenge and sorcery concludes. After her mother's marriage to the mysterious Lord Blackmore, Siobhan, last descendant of the Kings of Sudenne, is now supposed to be safe from the hostility of the sorcerer who rules the country. Too many mysteries remain, though, and the land itself calls for justice and the Lament of the Lost Moors to be heard. Will the young woman be able to avenge her father and defeat evil-and at what price?

Gauthier of Flanders hunts the Aa, a monster whose existence stains his family's honour and who is key to an alliance with the Jews of Samaria. Deep underground, the crusader and Osarias fight for their lives, while on the surface the Master of Machines plots to secure his own pacts and get rid of Robert of Taranto. In this terrible struggle for Hierus Halem, more lives, more souls will be lost to the terrible Qa'dj.

The Crusader army has been destroyed by the terrible Simoun Dja, the desert wind. Gauthier of Flanders has gone to look for the Jews of Samaria, possible allies to retake Jerusalem. But the Holy Land is rife with plots and counterplots. Christians and Muslims alike are torn by internal conflicts. And behind it all, pulling strings and offering temptations, one creature: the qa'dj-the demon that crept at the foot of the Cross.

The land of Eruin Dulea is ruled by a powerful and merciless sorcerer. A generation ago, he defeated his last challenger to the throne, Wulf, in a titanic battle. Wulf's widow, Lady O'Mara, and his daughter Siobhan can finally stop hiding, though. By marrying Lord Blackmore, Lady O'Mara places herself under his protection. But Siobhan is a strong-willed young woman, more at ease with a sword than a spinning wheel, and Blackmore himself isn't all he seems to be...

With the Master of Machines as their new leader, the Crusaders are ready to assault Jerusalem once more. The Sultan must now choose between his love for a Christian princess and his faith. And Gauthier of Flanders, to free his ally Osarias's Jewish people, will have to confront the last part of his mysterious past, a Jinni. As the final battle is joined, truths will be revealed on the nature of gods and demons and the ambitions of men.