Following on from, 'El mundo de las sombras' (The world of shadows), in the second part of this trilogy, Perséfone enters the world of intangibles accompanied by her beloved Gabriel. During a meeting in Istanbul, Ulla reveals her suspicions that Perséfone is the new Blue Queen, but Gabriel refuses to accept this. The Blue Queen is the only person capable of sweeping the intangibles into Pandemonium (the world of the dead), even against their will. Perséfone will have to fight against the dark force of Iskender, who is trying to form an army of 'the deceased', shadows repudiated by Pandemonium, in order to achieve the terrifying objective of destroying the boundaries that separate the worlds of life and death. The only way to find out if Ulla's prediction is right or not will be to confront them.